Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; Star block-copolymers; hybrid mesoscale simulation technique; rotational frequency; laboratory frame; Eckart frame; geometrical approach
Online: 22 June 2018 (15:12:59 CEST)
|
|
Share this article with
×
Star block-copolymers (SBCs) are macromolecules formed by a number of diblock copolymers anchored to a common central core, being the internal monomers solvophilic and the end monomers solvophobic. Recent studies have demonstrated that SBCs constitute a self-assembling building blocks with specific softness, functionalization, shape, and flexibility. Depending on different physical and chemical parameters the SBCs can behave as flexible patchy particles. In this paper, we study the rotational dynamics of isolated SBCs using a hybrid mesoscale simulation technique. We compare three different approaches to analyse the dynamics: the laboratory frame, the non-inertial Eckart's frame, and a geometrical approximation relating the conformation of the SBC to the velocity profile of the solvent. We find that the geometrical approach is adequate when dealing with very soft systems while in the opposite extreme, the dynamics is best explained using the laboratory frame. On the other hand, the Eckart frame is found to be very general and to reproduced well both extreme cases. We also compare the rotational frequency and the kinetic energy with the definitions of the angular momentum and inertia tensor different from recent publications.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Einstein's equation; gravitation; general relativity; sink; gravitational aether
Online: 22 June 2018 (06:19:33 CEST)
|
|
Share this article with
×
There exist some puzzles and difficulties related to Einstein's theory of general relativity. We generalize our previous theory of gravitation by methods of special relativistic continuum mechanics. In inertial coordinate systems, we construct a tensorial potential which satisfies the wave equation. Inspired by the equation of motion of a test particle, a definition of a metric tensor of a Riemannian spacetime is introduced. A generalized Einstein's equation is derived in inertial coordinate systems based on some assumptions. This equation reduces to Einstein's equation in case of weak field in harmonic coordinate systems. In some special non-inertial coordinate systems, a second generalized Einstein's equation is derived based on some assumptions. If the field is weak and the coordinate system is quasi-inertial and harmonic, the second generalized Einstein's equation reduces to Einstein's equation. There exists some differences between this theory and Einstein's theory of general relativity.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; MacDowell-Mansouri formalism; Bjorken-Zeldovich scale; Gauss-Bonnet term; Einstein-Cartan formalism; Big Bang Nucleosynthesis; cosmological constant; Kodama wavefunctions
Online: 22 June 2018 (06:14:04 CEST)
|
|
Share this article with
×
We discuss a possible scale of gravitational origin at around 10 MeV, or 10−12 cm, arisen in the MacDowell-Mansouri formalism of gravity due to the topological Gauss-Bonnet term in the action, pointed out by Bjorken several years ago. A length scale of the same size emerges also in the Kodama solution in gravity, which is known to be closely related to the MacDowell-Mansouri formulation. We particularly draw attention to the intriguing incident that existence of six compact extra dimensions originated from TeV-scale quantum gravity as well points to a length scale of 10−12 cm, as the compactification scale. The presence of six such extra dimensions is also in remarkable consistency with the MacDowell-Mansouri formalism; it provides a possible explanation for the factor of ~10120 multiplying the Gauss-Bonnet term in the action. We also comment on the relevant implications of such a scale regarding the thermal history of the universe motivated by the fact that it is considerably close to 1–2 MeV below which the weak interactions freeze out, leading to Big Bang Nucleosynthesis.
Preprint
|
|
|
Physical Sciences, Optics; gelatin; photosensitive materials; silver halide photographic emulsion; dichromated gelatin; selective tanning; short-wave UV radiation; photodestruction; diffraction efficiency; dyed gelatin; holographic structures; Weigert effect
Online: 21 June 2018 (08:13:26 CEST)
|
|
Share this article with
×
Because this issue journal is dedicated to Gelatin here we present a few applications of gelatin in the field of optics. It is understood that optics is the science that studies the production, propagation, interaction and detection of light. Regarding the detection there are some materials sensitive to light (photosensitive) that are used like photomultipliers, CCD’s, crystals, two dimension (2D) materials and more. Among the 2D materials the most popular through several centuries has been gelatin based photographic emulsion that records spatial distributions of light. More recently (1970) films made of Gelatin with Dichromate (DCG) and dyes have been used. We describe some characteristics and applications of these two photosensitive materials. Also we describe examples where gelatin is used as Relative Humidity (RH) sensor and in the fabrication of optical elements based on gelatin. This article is intended to researchers outside the optics community.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; galaxy morphology, machine learning; data analysis; object classification
Online: 18 June 2018 (16:12:10 CEST)
|
|
Share this article with
×
Automated machine classifications of galaxies are necessary because the size of upcoming surveys will overwhelm human volunteers. We improve upon existing machine classification methods by adding the output of SpArcFiRe to the inputs of a machine learning model. We use the human classifications from Galaxy Zoo 1 (GZ1) to train a random forest of decision trees to reproduce the human vote distributions of the Spiral class. We prefer the random forest model over other black box models like neural networks because it allows us to trace post hoc the precise reasoning behind the classification of each galaxy. We find that, across a sample of 470,000 Sloan galaxies that are large enough that details could be seen if they were there, the combination of SpArcFiRe outputs with existing SDSS features provides a better machine classification than either one alone on comparison to Galaxy Zoo 1. We suggest that adding SpArcFiRe outputs as features to any machine learning algorithm will likely improve its performance.
Preprint
|
|
|
Physical Sciences, Optics; ultra-low-loss waveguide; silicon photonics; heterogeneous integration; narrow linewidth lasers; high Q resonators.
Online: 18 June 2018 (15:39:38 CEST)
|
|
Share this article with
×
Integrated ultra-low-loss waveguides are highly desired for integrated photonics to enable applications that require long delay lines, high-Q resonators, narrow filters, etc. Here we present an ultra-low-loss silicon waveguide on 500 nm thick SOI platform. Meter-scale delay lines, million-Q resonators and tens of picometer bandwidth grating filters are experimentally demonstrated. We design a low-loss low-reflection taper to seamlessly integrate the ultra-low-loss waveguide with standard heterogeneous Si/III-V integrated photonics platform to allow realization of high-performance photonic devices such as ultra-low-noise lasers and optical gyroscopes.
Preprint
|
|
|
Physical Sciences, Optics; compound glass; microsphere; resonator; lasing; sensing
Online: 14 June 2018 (16:29:54 CEST)
|
|
Share this article with
×
In recent years, compound glass microsphere resonator devices have attracted increasing interest and have been widely used in sensing, microsphere lasers, and nonlinear optics. Compared with traditional silica resonators, compound glass microsphere resonators have many significant and attractive properties, such as high-Q factor, an ability to achieve high rare earth ion, wide infrared transmittance and low phonon energy. This review provides a summary and a critical assessment of the fabrication and the optical characterization of compound glasses and the related fabrication and applications of compound glass microsphere resonators.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; DyAl2, HoAl2, ErAl2, CEF, MFA, MCE, Atomic Matters.
Online: 14 June 2018 (14:48:55 CEST)
|
|
Share this article with
×
We present the results of calculations of magnetic properties of 3 compounds from Laves phase C15 family: DyAl2, HoAl2 and ErAl2 performed with a new computation system called ATOMIC MATTERS MFA. We compare these findings with the recently published results for TbAl2, GdAl2 and SmAl2. The calculation methodology was based on the localized electron approach applied to describe the thermal evolution electronic structure of rare-earth R3+ ions over a wide temperature range and to compute magnetocaloric effect (MCE). Thermomagnetic properties were calculated based on the fine electronic structure of 4f9, 4f10 and 4f11 configurations of the Dy3+, Ho3+, Er3+ ions, respectively. Our calculations yield the magnetic moment value and direction; single-crystalline magnetization curves in zero field and external magnetic field applied in various directions of m(T, Bext); the 4f-electronic components of specific heat c4f(T, Bext); and temperature dependence of the magnetic entropy and isothermal entropy change with external magnetic field -S(T, Bext). The cubic CEF parameter values used for DyAl2 calculations are taken from earlier research of A.L. Lima, A.O. Tsokol and recalculated for universal cubic parameters (Amn) for the RAl2 series. Our studies reveal the importance of multipolar charge interactions when describing thermomagnetic properties of real 4f electronic systems and the effectiveness of an applied self-consistent molecular field in calculations for magnetic phase transition simulation.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; charged dark matters; gravitation constant; Coulomb’s constant; dark energy density; particle creation; extended standard model
Online: 14 June 2018 (08:44:11 CEST)
|
|
Share this article with
×
The properties of the charged dark matters are discussed in terms of the new three-dimensional quantized space model. Because of the graviton evaporations, the very small Coulomb’s constant (k(dd)) of 10-48 k and large gravitation constant (GN(dd)) of 106 GN for the charged dark matters at the present time are expected. The tentative values of G and k are used for the explanation purpose. Therefore, Fc(mm) > Fg(dd) > Fg(mm) > Fg(dm) > Fc(dd) > Fc(dm) = 0 for the proton-like particle. Also, the gravitation constant has been changed with increasing of the time because of the graviton evaporation. In the present work, the B1, B2 and B3 bastons with the condition of k(mm) = k >> k(dd) > k(dm) = 0 are explained as the good candidates of the dark matters. Also, the particle creation, dark matters and dark energy could be deeply associated with the changing gravitation constants (G). It is expected that the changing process of the gravitation constant between the matters from GN(mm) ≈ 1036 GN to GN(mm) = GN happened mostly near the inflation period. Therefore, during most of the universe evolution the gravitation constant could be taken as GN(mm) = GN. And the effective charges and effective rest masses of the particles are defined in terms of the fixed Coulomb’s constant (k) and fixed gravitation constant (GN). Then, the effective charge of the B1 dark matter with EC = −2/3 e is (EC)eff = −2/3·10−24 e.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; spacetime models; discrete spacetime; relativity theory; causal models; quantum field theory; spin networks; quantum loops
Online: 12 June 2018 (12:43:15 CEST)
|
|
Share this article with
×
Based on a local causal model of the dynamics of curved discrete spacetime, a causal model of quantum field theory in curved discrete spacetime is described. On the elementary level, space(-time) is assumed to consists of interconnected space points. Each space point is connected to a small discrete set of neighboring space points. Density distribution of the space points and the lengths of the space point connections depend on the distance from the gravitational sources. This leads to curved spacetime in accordance with general relativity. Dynamics of spacetime (i.e., the emergence of space and the propagation of space changes) dynamically assigns "in-connections" and "out-connections" to the affected space points. Emergence and propagation of quantum fields (including particles) are mapped to the emergence and propagation of space changes by utilizing identical paths of in/out-connections. Compatibility with standard quantum field theory (QFT) requests the adjustment of the QFT techniques (e.g., Feynman diagrams, Feynman rules, creation/annihilation operators), which typically apply to three in/out connections, to n > 3 in/out connections. In addition, QFT computation in position space has to be adapted to a curved discrete space-time.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; FeSe2; high pressure; low temperature; single crystal diffraction
Online: 12 June 2018 (10:25:24 CEST)
|
|
Share this article with
×
We conducted an in-situ crystal structure analysis of ferroselite at non-ambient conditions. The aim is to provide a solid ground to further the understanding of the properties of this material in a broad range of conditions. Ferroselite, marcasite-type FeSe2, was studied under high pressures up to 46 GPa and low temperatures, down to 50 K using single-crystal microdiffraction techniques. High pressure and low temperatures were generated using a diamond anvil cell and a cryostat. We found no evidences of structural instability in the explored P-T space. The deformation of the orthorhombic lattice is slightly anisotropic. As expected, the compressibility of the Se-Se dumbbell, the longer bond in the structure, is larger than that of the Fe-Se bonds. Less obvious is the behavior of the octahedral bonds, the shorter bond is the most compressible determining a small increase in the octahedron distortion with pressure. We also achieved a robust structural analysis of ferroselite at low temperature in the diamond anvil cell. Structural changes upon temperature decrease are small but qualitatively similar to those produced by pressure.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; cosmology: theory; gravitation; early universe; dark energy; large-scale structure of universe; cosmic background radiation; neutrinos
Online: 12 June 2018 (08:43:45 CEST)
|
|
Share this article with
×
A new model of cosmology is proposed, where the state of high energy density commonly associated with the big bang is generated by the collapse of an antineutrino star that has exceeded its Chandrasekhar limit. To allow the first neutrino stars and antineutrino stars to form naturally from an initial quantum vacuum state, matter and antimatter are assumed to gravitationally repel. In this scenario, a degenerate antineutrino star in effective hydrostatic equilibrium has a density that is similar to the dark energy density of the ΛCDM model. When viewed from the core, such a star could today accelerate matter radially and emit the isothermal cosmic microwave background radiation, which addresses the horizon and flatness problems. This model and the ΛCDM model are in similar quantitative agreement with supernova distance measurements. The presented model is also in qualitative agreement with observed large-scale anisotropy and inhomogeneity, which distinguishes it from the ΛCDM model.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; rogue; wave; models; KdV; NLSE; non-local; ocean; optics
Online: 9 June 2018 (15:28:58 CEST)
|
|
Share this article with
×
Anomalous waves and rogue events are closely associated with irregularities and unexpected events occurring at various levels of physics, such as in optics, in oceans and in the atmosphere. Mathematical modeling of rogue waves is a highly actual field of research, which has evolved over the last decades into a specialized part of mathematical physics. The applications of the mathematical models for rogue events is directly relevant to technology development for prediction of rogue ocean waves, and for signal processing in quantum units. In this survey, a comprehensive perspective of the most recent developments in methods for representing rogue waves is given, along with discussion of the devised and forms and solutions. The standard nonlinear Schrödinger equation, the Hirota equation, the MMT equation and further to other models are discussed, and their properties highlighted. This survey shows that the most recent advancement in modeling rogue waves give models which can be used to establish methods for prediction of rogue waves at open seas, which is important for the safety and activity of marine vessels and installations. The study further puts emphasis on the difference between the methods, and how the resulting models form a basis for representing rogue waves in various forms, solitary or with a wave-background. This review has also a pedagogic component directed towards students and interested non-experts, and forms a complete survey of the most conventional and emerging methods published until recently
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; entropic gravity; MOND; dark matter
Online: 8 June 2018 (12:40:57 CEST)
|
|
Share this article with
×
In this article a simplified view is given on Verlinde’s entropic gravity. It reveals several shortcomings in the theory. This holds in particular for the inclusion of the dark matter effect in the derived modified expression for the Newtonian gravitational acceleration. Although the merit of the entropic view on gravity is recognized, the proposed explicit axiomatic hypothesis as a basis is criticized. There is no reason why it should be preferred above Einstein’s Field Equation.
Preprint
|
|
|
Physical Sciences, Other; quantum information; quantum dynamics; entanglement
Online: 4 June 2018 (11:03:21 CEST)
|
|
Share this article with
×
Quantum Computation, in the gate array version, uses logical gates adopting convenient forms for computational algorithms based on those of classical computation. There, two-level quantum systems are the basic elements connecting the binary nature of classical computation with the settlement of quantum processing. Despite, their design depends on specific quantum systems and physical interactions involved, exacerbating the dynamics analysis. Predictable and controllable manipulation should be addressed to control the quantum states, but resources are restricted to limitations imposed by the physical settlement. This work presents a formalism to decompose the quantum information dynamics in SU(22d) for 2d-partite two-level systems into 22d-1 SU(2) quantum subsystems. Decomposition lets to set control procedures, to generate large entangled states and to design specialized dedicated quantum gates. There, easy and traditional operations proposed by quantum computation are recovered for more complex and large systems. Alternating the parameters of local and non-local interactions, the procedure states a universal exchange semantics on the generalized Bell states basis. It could be understood as a momentary splitting of the 2d information channels into 22d-1 pairs of 2 level quantum information subsystems and a settlement of the quantum information manipulation free of the imposed restrictions by the underlying physical system.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; 4th order gravity; quantum potential; ER = EPR; wormholes
Online: 1 June 2018 (11:47:41 CEST)
|
|
Share this article with
×
A classical origin for the quantum potential, as that potential term arises in the quantum mechanical treatment of black holes and Einstein-Rosen (ER) bridges, can be based on 4th-order extensions of Einstein's equations. The 4th-order extension of general relativity required to generate a Bohmian quantum potential is given by adding quadratic curvature terms with coefficients that maintain a fixed ratio, as their magnitudes approach zero. Black hole radiation, and the analogous process of quantum transmission through an ER bridge, can then be described classically. Quantum transmission through the classically non-traversable bridge is replaced by classical transmission through a traversable wormhole. If entangled particles are connected by a Planck-width ER bridge, as conjectured by Maldacena and Susskind, then the classical wormhole transmission effect gives the ontological nonlocal connection between the particles posited in Bohm's interpretation of their entanglement. It is hypothesized that higher-derivative extensions of classical gravity can account for the nonlocal part of the quantum potential generally.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; gravitational lenses; hubble constant; cosmology
Online: 31 May 2018 (11:43:05 CEST)
|
|
Share this article with
×
We consider an alternative formula for time delay in gravitational lensing. Imposing a smoothness condition on the gravitationally deformed paths followed by the photons from the source to the observer, we show that our formula displays the same degrees of freedom of the standard one. In addition to this, it is shown that the standard expression for time delay is recovered when small angles are involved. These two features strongly support the claim that the formula for time delay studied in this paper is the generalization to arbitrary angles of the standard one, which is valid at small angles. This could therefore result in a useful tool in view of softening the known discrepancy between the various estimates of the Hubble constant. As an aside, two interesting consequences of our proposal for time delay are discussed: the existence of a constraint on the gravitational potential generated by the lens and a formula for the mass of the lens in the case of central potential.
Preprint
|
|
|
Physical Sciences, Optics; optical frequency domain reflectometry; distributed sensor; temperature sensor; tunable laser; coated fiber
Online: 31 May 2018 (11:41:37 CEST)
|
|
Share this article with
×
We present a distributed optical-fiber temperature sensor with enhanced sensitivity based on an Al-coated fiber using the Rayleigh backscattering spectra (RBS) shift in optical frequency-domain reflectometry (OFDR). The Al-coated sensing fiber with a higher thermal expansion coefficient compared to silica produces a strain-coupled shift in the RBS under an increase in temperature. This effect leads to an enhanced temperature sensitivity of the distributed measurement scheme. Our results revealed that the temperature sensitivity obtained using the Al-coated fiber in OFDR was ~56% higher relative to that of a single-mode fiber. Moreover, the minimum measurable temperature recorded was 1 °C with a spatial resolution of 5 cm.
Preprint
|
|
|
Physical Sciences, Optics; nanoparticles; microscopic electron dynamics; nonlocality; light interaction; theory and simulation
Online: 31 May 2018 (10:47:41 CEST)
|
|
Share this article with
×
Nanoparticles -- regularly patterned or randomly dispersed -- are a key ingredient for emerging technologies in photonics. Of particular interest are scattering and field enhancement effects of metal nanoparticles for energy harvesting and converting systems. An often neglected aspect in the modeling of nanoparticles are light interaction effects beyond classical electrodynamics stemming from electron dynamics in confined and accelerated systems. We give a detailed account on free electron phenomena in metal nanoparticles and discuss analytic expressions, stemming from microscopic and semi-classical theories. These can improve standard computational schemes to produce more reliable results on the optical properties of metal nanoparticles. We combine these solutions into a single framework and study their joint impact on isolated Au, Ag, and Al nanoparticles as well as dimer structures.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; white dwarfs; burning in stars; plasma diagnostics; atomic spectra; plasma spectroscopy; laser spectroscopy; laser-induced breakdown spectroscopy
Online: 31 May 2018 (05:13:00 CEST)
|
|
Share this article with
×
This work communicates a review on Balmer series hydrogen beta line measurements and applications for analysis of white dwarf stars. Laser-induced plasma investigations explore electron density and temperature ranges comparable to white dwarf star signatures such as Sirius B, the companion to the brightest star observable from the earth. Spectral line shape characteristics of the hydrogen beta line include width, peak separation, and central dip-shift, thereby providing three indicators for electron density measurements. The hydrogen alpha line shows two primary line-profile parameters for electron density determination, namely, width and shift. Both Boltzmann plot and line-to-continuum ratios yield temperature. The line-shifts recorded with temporally- and spatially- resolved optical emission spectroscopy of hydrogen plasma in laboratory settings can be larger than gravitational redshifts that occur in absorption spectra from radiating white dwarfs. Published astrophysical spectra display significantly diminished Stark or pressure broadening contributions to red-shifted atomic lines. Gravitational redshifts allow one to assess the ratio of mass and radius of these stars, and subsequently, the mass from cooling models.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; drop; cusp instability; encapsulation
Online: 30 May 2018 (09:08:41 CEST)
|
|
Share this article with
×
The rising of an oil drop in a non-Newtonian viscous solution is studied experimentally. In this case, the shape of the ascending drop is strongly affected by the non-Newtonian properties of the surrounding liquid. We found that the so-called velocity discontinuity phenomena is observed for drops larger than a certain critical size. Beyond the critical velocity, the formation of a long tail is observed, from which small droplets are continuously emitted. We determined that the fragmentation of the tail results mainly from the effect of capillary effects. We explore the idea of using this configuration as a new encapsulation technique, where the size and frequency of droplets can be well predicted.
Preprint
|
|
|
Physical Sciences, Acoustics; underwater acoustic communication; parametric technique; self-demodulation
Online: 28 May 2018 (09:42:15 CEST)
|
|
Share this article with
×
This paper presents a study of different types of parametric signals with application to underwater acoustic communications. In all the signals, the carrier frequency is 200 kHz, which corresponds to the resonance frequency of the transducer under study and different modulations are presented and compared. In this sense, we study modulations with parametric sine sweeps (4 to 40 kHz) that represent binary codes (zeros and ones), getting closer to the application in acoustic communications. The different properties of the transmitting signals in terms of bit rate, directivity, efficiency and power needed are discussed as well.
Preprint
|
|
|
Physical Sciences, Radiation & Radiography; magnetic resonance imaging; arterial spin labelling; renal MRI; perfusion; renal ASL
Online: 28 May 2018 (06:26:31 CEST)
|
|
Share this article with
×
Purpose: A number of imaging readout schemes have been proposed for renal arterial spin labelling (ASL) to quantify kidney cortex perfusion, including gradient echo based methods of balanced fast field echo (bFFE) and gradient-echo echo-planar imaging (GE-EPI), or spin echo based schemes of spin-echo echo planar imaging (SE-EPI) and turbo spin-echo (TSE). Here, we compare these imaging schemes to evaluate the optimal imaging scheme for pulsed ASL (PASL) assessment of human kidney cortex perfusion at 3 T. Methods: Ten healthy volunteers with normal renal function were scanned using each 2D multislice imaging scheme, in combination with a respiratory triggered FAIR (flow-sensitive alternating inversion recovery) ASL scheme on a 3 T Philips Achieva scanner. All volunteers returned for a second identical scan session within two weeks of the first scan session. Comparisons were made between the imaging schemes in terms of perfusion weighted image (PWI) signal-to-noise ratio (SNR) and perfusion quantification, temporal SNR (tSNR), spatial coverage, and repeatability. Results: For each imaging scheme, renal cortex perfusion was calculated (bFFE: 276 ± 29 mL/100 g/min, GE-EPI: 222 ± 18 mL/100 g/min, SE-EPI: 201 ± 36 mL/100 g/min, TSE: 200 ± 20 mL/100 g/min). Perfusion was found to be higher for GE based readouts compared to SE based readouts, with significantly higher measured perfusion for the bFFE readout compared to all other schemes (P < 0.05), attributed to the greater vascular signal present. Despite the PWI-SNR being significantly lower for SE-EPI compared to all other schemes (P < 0.05), the SE-EPI readout gave the highest tSNR and was found to be the most reproducible scheme for the assessment of kidney cortex, with a CoV of 17.2%, whilst minimizing variability of the perfusion weighted signal across slices for whole kidney perfusion assessment. Conclusion: For the assessment of kidney cortex perfusion, SE-EPI provides optimal tSNR, minimal variability across slices and repeatable data acquired in a short scan time with low specific absorption rate.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; water; DNA; wave; topoisomerase
Online: 24 May 2018 (09:58:08 CEST)
|
|
Share this article with
×
Recently, some authors have shown that life can be emerged in pure water. We
con rm this claim and propose a mechanism for extracting DNA from pure water.
In this model, water has two structures which are the same in four dimensions and
di erent in extra dimensions. These structure are similar to the structures of DNAs
of men and women in extra dimensions. This helps the water to store two di erent
informations of DNAs. Some special waves can interact with water and extract it's
structure from extra dimension. These waves act like topoisomerases in biology on
11-dimensional manifold.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; extra dimensions; water; wave; manifold
Online: 22 May 2018 (13:05:51 CEST)
|
|
Share this article with
×
In this paper, we consider the structure of water and waves from viewpoints of two observers, one lives on 4-dimensional manifold and another lives on 11-dimensional manifold. On four dimensional manifold, if a water contains molecules of DNA, emits waves that by achieving to second water, give their information to it and produce new structures which are affected by the existence of DNA molecules and can be detected by PCR. Type of packings of DNAs in men is di erent from women. Consequently, their radiated waves are different and for storing their information, we need to two types of water. However on four dimensional manifold, the structures of water are approximately the same. There is a probability that di erences between various types of water could be observed in extra dimensions. On the other hand, waves that interact with water in extra dimensions can play the role of topoisomerases in biology on 11-dimensional manifold. They open packings of DNA, read it's information and transmit it to water. Properties of these topoisomerase-like waves are di erent from electromagnetic and gravitational waves. However,by reducing dimensions from 11 to 4, these waves become similar to known waves in four dimensions. Two structures of water and wave in extra dimensions have effects in nature. For example, waters inside the egg of women and water outside it have di erent structures which causes to the emergence of the entanglement between them. If sperms enter to water outside the egg, this entanglement is broken and some holes are appeared inside the egg. To fill these holes, sperms are teleported from water outside the egg to water inside the egg. Another effect is radiating some topoisomerase like waves of earth and sun which are helpful for plants and transcription and translation in cells. In some conditions, these waves interact with water, extract DNAs from it's structure in extra dimensions and create life.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; quantum metrology; fermionic gaussian state; quantum geometric information
Online: 22 May 2018 (05:52:11 CEST)
|
|
Share this article with
×
In this article we derive a closed form expression for the symmetric logarithmic derivative of Fermionic Gaussian states. This provides a direct way of computing the quantum Fisher Information for Fermionic Gaussian states. Applications range from quantum Metrology with thermal states to non-equilibrium steady states with Fermionic many-body systems.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; DNA, 11-dimensions, Wave, Topoisomerase
Online: 21 May 2018 (16:40:31 CEST)
|
|
Share this article with
×
In this paper, we propose a new model which allows to consider all evolutions of DNA from viewpoint of an observer on 11-dimensional manifold. In this model, DNA is an 4 + n-dimensional object in 11 dimensional space-time which is compacted to 4-dimensional manifold. This leads to the emergence of a curved space-time around DNA and production of some new waves. To exchange information between DNAs, it is needed that waves play the role of topoisomerases in extra dimensions. These topoisomerase-like waves open packings of DNA, read it’s information and compact it again. The shape and properties of these waves are completely different from gravitational and electromagnetic ones. By reducing dimensions from 11 to 4, the topoisomerase-like waves obtain the properties of known fields like gravitons and photons.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Heisenberg's uncertainty principle; certainty; wave function; Planck scale; Planck mass; Planck particle; Bell's inequality; superposition; entropy
Online: 18 May 2018 (08:01:26 CEST)
|
|
Share this article with
×
In this paper, we will revisit the derivation of Heisenberg's uncertainty principle. We will see how the Heisenberg principle collapses at the Planck scale by introducing a minor modification. The beauty of our suggested modification is that it does not change the main equations in quantum mechanics; it only gives them a Planck scale limit where uncertainty collapses. We suspect that Einstein could have been right after all, when he stated, ``God does not throw dice." His now-famous saying was an expression of his skepticism towards the concept that quantum randomness could be the ruling force, even at the deepest levels of reality. Here we will explore the quantum realm with a fresh perspective, by re-deriving the Heisenberg principle in relation to the Planck scale. Our modified theory indicates that renormalization is no longer needed. Further, Bell's Inequality no longer holds, as the breakdown of Heisenberg's uncertainty principle at the Planck scale opens up the possibility for hidden variable theories. The theory also suggests that the superposition principle collapses at the Planck scale. Further, we show how this idea leads to an upper boundary on uncertainty, in addition to the lower boundary. These upper and lower boundaries are identical for the Planck mass particle; in fact, they are zero, and this highlights the truly unique nature of the Planck mass particle.
Preprint
|
|
|
Physical Sciences, Optics; optical vortices; topological charge; shear interference; mode superposition
Online: 17 May 2018 (13:26:46 CEST)
|
|
|
Share this article with
×
Optical modes bearing optical vortices are important light systems in which to encode information. Optical vortices are robust features of optical beams that do not dissipate upon propagation. Thus decoding the modal content of a beam is a vital component of the process. In this work we present a method to decode modal superpositions of light beams that contain optical vortices. We do so using shear interferometry, which presents a simple and effective means of determining the vortex content of a beam, and extract the parameters of the component vortex modes that constitute them. We find that optical modes in a beam are easily determined. Its modal content can be extracted when they are of comparable magnitude. The use of modes of well defined topological charge but not well defined radial-mode content, such as those produced by phase-only encoding, are much easier to diagnose than pure Laguerre-Gauss modes.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; fermionic dark matters; neutron life-time anomaly; massive graviton; hadronization; dark energy; galaxy structure; three-dimensional quantized space model
Online: 15 May 2018 (06:16:23 CEST)
|
|
|
Share this article with
×
The properties of the dark matters, dark energy, graviton and photon are discussed in terms of the new three-dimensional quantized space model. Three new particles (bastons) with the electric charges (EC) are proposed as the dark matters. The decreasing coupling constant of the strong force and neutron lifetime anomaly are explained by the unobservable proton and hadronization. And the rest mass of 1.4 TeV/c2 is assigned to the Le particle with the EC charge of −2e. The proposed rest mass (26.12 eV/c2) of the B1 dark matter is indirectly confirmed from the supernova 1987A data. It is proposed that the EC, LC and CC charges are aligned along the time axes but not along the space axes. The photon is confined on its corresponding three-dimensional quantized space. However, the graviton can be evaporated into other three-dimensional quantized spaces. The rest mass and force range of the massive g(0,0,0) graviton with the Planck size are mg = 3.1872·10−31 eV/c2 and xr = 3.0955·1023 m = 10.0 Mpc, respectively, based on the experimental rest mass and rms charge radius of the proton. The possible diameter (10 Mpc) of the largest galaxy cluster is remarkably consistent with the gravitational force range (10 Mpc). Then, the diameter of the largest dark matter distribution related to the largest galaxy cluster is 9.2865·1023 m = 30 Mpc equal to the force range of the massive g(0) graviton with the rest mass of 1.0624·10−31 eV/c2. The reason why the gravitational force between normal matters is very weak when compared with other forces is explained by the graviton evaporation and photon confinement. Because of the huge number (N) of the evaporated gravitons into the x1x2x3 space, it is concluded that the gravitational force between dark matters should be much stronger than the gravitational force between the normal matters and the repulsive electromagnetic force between dark matters. The proposed weak gravitational force between the dark matters and normal matters explains the observed dark matter distributions of the bullet cluster, Abell 1689 cluster and Abell 520 cluster. The transition from the galaxy without the dark matters to the galaxy with the dark matters are explained. Also, the accelerated space expansion is caused by the new space quanta created by the evaporated gravitons into the x1x2x3 space and repulsive electromagnetic force between dark matters corresponding to the dark energy. And the space evolution can be described by using these graviton evaporation and repulsive electromagnetic force, too.
Preprint
|
|
|
Physical Sciences, Applied Physics; graphene; two-dimensional materials; nonlinear quantum circuits; quantum bits
Online: 15 May 2018 (05:29:06 CEST)
|
|
Share this article with
×
In this letter, it is proposed that cryogenic quantum bits could operate based on the nonlinearity due to the quantum capacitance of two-dimensional Dirac materials, and in particular graphene. The anharmonicity of a typical superconducting quantum bit is calculated and the sensitivity of quantum bit frequency and anharmonicty with respect to temperature are found. Reasonable estimates reveal that a careful fabrication process could reveal the expected properties, thus putting the context of quantum computing hardware into new perspectives.
Preprint
|
|
|
Physical Sciences, Optics; optical tweezers; optical trapping; viscosity; direct laser writing; 3D lithography; two-photon polymerization; micro-tool
Online: 14 May 2018 (08:56:11 CEST)
|
|
Share this article with
×
Manipulation of micro- and nano-sized objects with optical tweezers is a well established, albeit still evolving technique. While many objects can be trapped directly with focused laser beam(s), for some applications indirect manipulation with tweezers-operated tools is preferred. We introduce a simple, versatile micro-tool operated with holographic optical tweezers. The 40 µm long dumbbell-shaped tool, fabricated with two-photon laser 3D photolithography has two beads for efficient optical trapping and a probing spike on one end. We demonstrate fluids viscosity measurements and vibration detection as examples of possible applications.
Preprint
|
|
|
Physical Sciences, Radiation & Radiography; gel dosimetry; radiation dosimetry; radio-fluorogenic gel, luminescent dosimetry
Online: 11 May 2018 (05:29:00 CEST)
|
|
Share this article with
×
In radiotherapy, accurate deposition of energy to the targeted volume is vital to ensure effective treatment. Gel dosimeters are attractive detection systems, as tissue substitutes with potential to yield three-dimensional dose distributions. Radio-fluorogenesis is creation fluorescent chemical products in response to energy deposition from high-energy radiation. This report shares studies of a radio-fluorogenic gel dosimetry system, gelatin with coumarin-3-carboxlyic acid (C3CA), for the quantification of imparted energy. Aqueous solutions exposed to ionizing radiation result in the production of hydroxyl free radicals through water radiolysis. Interactions between hydroxyl free radicals and coumarin-3-carboxylic acid produce a fluorescent product. 7-hydroxy-coumarin-3-carboxylic acid has a blue (445 nm) emission, following UV to near UV (365–405 nm) excitation. Effects of C3CA concentration and pH buffers were investigated for this system. The response of the system was explored with respect to strength, type, and exposure rate of high-energy radiation. Results show a linear dose response relationship with a dose-rate dependency and no energy or type dependencies. This report supports the utility of gelatin-C3CA for phantom studies of radio-fluorogenic processes.
Preprint
|
|
|
Physical Sciences, Mathematical Physics; monte-carlo simulations; burgers equation; langevin equation; fractional velocity
Online: 10 May 2018 (06:11:01 CEST)
|
|
Share this article with
×
The present work is concerned with the study of the generalized Langevin equation and its link to the physical theories of statistical mechanics and scale relativity. It is demonstrated that the form of the coefficients of Langevin equation depend critically on the assumption of continuity of the reconstructed trajectory. This in turn demands for the fluctuations of the diffusion term to be discontinuous in time. This paper further investigates the connection between the scale-relativistic and stochastic mechanics approaches, respectively, with the study of the Burgers equation, which in this case appears as a stochastic geodesic equation. By further demanding time reversibility of the drift the Langevin equation can also describe equivalent quantum-mechanical systems in a path-wise manner. The resulting statistical description obeys the Fokker-Plank equation of the probability density of the differential system, which can be readily estimated from Monte Carlo simulations of the random paths. Based on the Fokker-Plank formalism a new derivation of the transient probability densities is presented. Finally, stochastic simulations are compared to the theoretical results.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; general relativity; theory of information; tilted spacetimes
Online: 10 May 2018 (05:30:51 CEST)
|
|
Share this article with
×
The fact that real dissipative (entropy producing) processes may be detected by non–comoving observers (tilted), in systems that appear to be isentropic for comoving observers, in general relativity, is explained in terms of the information theory, in analogy with the explanation of the Maxwell's demon paradox.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; entanglement; hydrodynamic analogs of quantum systems; Bell's inequalities; Bohmian mechanics
Online: 8 May 2018 (08:43:29 CEST)
|
|
Share this article with
×
We describe results from a Monte-Carlo simulation of Bell-CHSH type correlations in hydrodynamic walkers. We study feasibility of a real life walker test with relevant hydrodynamic parametric ranges. We observe the generic formation of pairs of walkers strongly anti-correlated both in position and momentum. With this source of entangled walkers, we model the insertion of 2 pins in the bath as a notion of measure, akin to the polarizers of photonic Bell tests. This insertion of pins, either static or dynamic, introduces 2 weak field signals. Each field has the physical form of a standing wave Bessel hat, representing the non-local (field mediated) influences of the measure on the walkers. With this representation of the measure, we develop protocol for a Bell game with actual hydrodynamic walkers. We model both static and dynamic insertion of pins in the walker bath. Static pins give us numerical S > 2, as a permissible Bell violation for a non-local (field based) effect. Dynamic insertion of the pins, however, leads to causal space separation of the two arms. We observe the again expected S ≤ 2. We argue for the hydrodynamic implementation and observation of these effects as a walker visualization of Bell inequalities.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; quantum field theory; local causal models; general relativity theory; spacetime models; discrete spacetime; computer simulations
Online: 7 May 2018 (05:45:19 CEST)
|
|
Share this article with
×
Based on a local causal model of the dynamics of curved discrete spacetime, a causal model of quantum field theory in curved discrete spacetime is described. At the elementary level, space(-time) is assumed to consists of interconnected space points. Each space point is connected to a small discrete set of neighbor space points. Density distribution of the space points and the lengths of the space point connections depend on the distance from the gravitational sources. This leads to curved spacetime in accordance with general relativity. Dynamics of spacetime (i.e., the emergence of space and the propagation of space changes) dynamically assigns "in-connections" and "out-connections" to the affected space points. Emergence and propagation of quantum fields (including particles) are mapped to the emergence and propagation of space changes by utilizing identical paths of in/out-connections. Compatibility with standard quantum field theory (QFT) requests the adjustment of the QFT techniques (e.g., Feynman diagrams, Feynman rules, creation/annihilation operators), which typically apply to three in/out connections, to n > 3 in/out connections. In addition, QFT computation in position space has to be adapted to a curved discrete space-time.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; Kondo Lattice; localized moments; ferromagnetic correlations
Online: 3 May 2018 (12:03:16 CEST)
|
|
Share this article with
×
We study the electron spin resonance (ESR) line width for localized moments within the framework of the Kondo lattice model. An ESR signal for an impurity can only be observed if the Kondo temperature is sufficiently small. On the other hand, for the Kondo lattice, short-range ferromagnetic correlations (FM) between the localized spins are necessary to obtain an observable signal. The spin relaxation rate (line width) is inversely proportional to the static magnetic susceptibility. The FM enhance the susceptibility and hence reduce the line width. For most of the heavy fermion systems displaying an ESR signal the FM arise in the ab-plane from the strong lattice anisotropy. An ESR signal was observed in the cubic heavy fermion compound CeB6 which has a Γ8 ground-quartet. The orbital content of the Γ8-quartet gives rise to an antiferro-quadrupolar ordered (AFQ) phase below 4 K. Single ions with a Γ8 ground-multiplet are expected to display four transitions, however, only one has been observed. We address the effects of the interplay of AFQ and FM on the phase diagram and the ESR line width. While for anisotropic Ce and Yb compounds with ESR-signal it is difficult to distinguish if the resonance is due to localized spins or conducting heavy electron spins, an itinerant picture within the AFQ phase is necessary to explain the electron spin resonances for CeB6. The longitudinal magnetic susceptibility has a quasi-elastic central peak of line width 1/T1 and inelastic peaks for the absorption/emission of excitation. The latter are measured via inelastic neutron scattering (INS) and provide insights into the magnetic order. We briefly summarize some of the INS results for CeB6 in the context of the picture that emerged from the ESR experiments.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; bioclimatic design; climatic conditions; wind tunnel; numerical methods; social housing; energy efficiency
Online: 3 May 2018 (11:26:27 CEST)
|
|
Share this article with
×
This paper presents the results of aerodynamical performance research focused on maintaining the thermal comfort and increasing the energy efficiency of a typical social housing unit located in a high-density urban area. Bioclimatic design strategies are used to develop a sustainable and economic technology in existing housing clusters in Mexico City. A full-scale prototype, built on campus facilities, was used to study the flow conditions around the design. All scaled prototypes implement similar criterion. Furthermore, a scaled prototype is evaluated within a low speed wind tunnel installation. Additionally, numerical simulations were performed at transient state based on previous physical measurements and historical local climatic conditions to determine preferable modifications.
Preprint
|
|
|
Physical Sciences, Other; magneto-optics; magnetic thin films; optical constants
Online: 3 May 2018 (08:59:50 CEST)
|
|
Share this article with
×
This work is devoted to physical vapor deposition synthesis, and characterisation of bismuth and lutetium-substituted ferrite-garnet thin-film materials for magneto-optic (MO) applications. The properties of garnet thin films sputtered using a target of nominal composition type Bi0.9Lu1.85Y0.25Fe4.0Ga1O12 are studied. By measuring the optical transmission spectra at room temperature, the optical constants and the accurate film thicknesses can be evaluated using Swanepoel’s envelope method. The refractive index data are found to be matching very closely to these derived from Cauchy’s dispersion formula for the entire spectral range between 300-2500 nm. The optical absorption coefficient and the extinction coefficient data are studied for both the as-deposited and annealed garnet thin-film samples. A new approach is applied for accurately deriving the optical constants data simultaneously with the physical layer thickness, using a combination approach employing custom-built spectrum-fitting software in conjunction with Swanepoel’s envelope method. MO properties, such as specific Faraday rotation, MO figure of merit and MO swing factor are also investigated for several annealed garnet-phase films.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; path; inference; fluids; maximum entropy; maximum caliber
Online: 2 May 2018 (11:58:32 CEST)
|
|
Share this article with
×
A general framework for inference in dynamical systems is described, based on the language of Bayesian probability theory and making use of the maximum entropy principle. Taking as fundamental the concept of a path, the continuity equation and Cauchy's equation for fluid dynamics arise naturally, while the specific information about the system can be included using the Maximum Caliber (or maximum path entropy) principle.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Fokker-Planck equations; fermion statistics; boson statistics; Haldane statistics; Kinetic interaction principle; anomalous diffusion; Fokker-Planck current
Online: 2 May 2018 (11:36:35 CEST)
|
|
Share this article with
×
Master equations define the dynamics that govern the time evolution of various physical processes on lattices. In the continuum limit, master equations lead to Fokker-Planck partial differential equations that represent the dynamics of physical systems in continuous spaces. Over the last few decades, nonlinear Fokker-Planck equations have become very popular in condensed matter physics and in statistical physics. Numerical solutions of these equations require the use of discretization schemes. However, the discrete evolution equation obtained by the discretization of a Fokker-Planck partial differential equation depends on the specific discretization scheme. In general, the discretized form is different from the master equation that has generated the respective Fokker-Planck equation in the continuum limit. Therefore, the knowledge of the master equation associated with a given Fokker-Planck equation is extremely important for the correct numerical integration of the latter, since it provides a unique, physically motivated discretization scheme. This paper shows that the Kinetic Interaction Principle (KIP) that governs the particle kinetics of many body systems, introduced in [G. Kaniadakis, Physica A 296, 405 (2001)], univocally defines a very simple master equation that in the continuum limit yields the nonlinear Fokker-Planck equation in its most general form.
Preprint
|
|
|
Physical Sciences, Applied Physics; solar windows; advanced glazings; low-emissivity spectrally-selective coatings; photovoltaics
Online: 2 May 2018 (08:23:36 CEST)
|
|
Share this article with
×
A study of photovoltaic solar window technologies is reported, focusing on their structural features, functional materials, system development, and suitability for use in practical field applications, e.g. public infrastructures and agricultural installations. Energy generation performance characteristics are summarized and compared to theory-limit predictions. Working examples of pilot-trial solar window-based installations are described. We also report on achieving electric power outputs of about 25 Wp/m2 from clear and transparent large-area glass-based solar windows.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; special relativity; quantum mechanics; non-locality; Planck’s constant; EPR
Online: 1 May 2018 (08:40:03 CEST)
|
|
Share this article with
×
The nonlocality of entangled quantum mechanical systems is incompatible with the standard interpretation of special relativity as a single 4D Minkowskian metric spacetime. The difficulty is that the definition of a spacetime interval between any pair of events precludes any form of nonlocal interaction, even the relatively benign non-signaling correlations. By an application of the relativity principle, and the use of the space ←→ time symmetry of the Lorentz boost I propose here a reinterpretation of special relativistic spacetime. This new ontology consists of a set of coexisting 3+1D spaces (‘framespaces’), each containing unique content in the form of a complex density. These spaces are related by the Lorentz boost, and coupled pairwise in a manner dictated by the Lorentz transformation. The inter-space coupling acting on the spacetime content gives rise to a nonlocal wave phenomenon, which is identified as quantum wave mechanics. The interspace coupling strength is then inversely proportional to Planck’s constant. The coexistence of multiple spaces is interpreted as momentum superposition, implying that momentum is the fundamental physical basis of quantum superposition. This new spacetime interpretation of quantum mechanics has many consequences, including explanations of quantum non-locality, the spacetime role of Planck’s constant, quantum measurement as a symmetry-breaking process and the redundancy of description of gauge theory.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Cosmology; Lyra Geometry; Linearly Varying Deceleration Parameter
Online: 30 April 2018 (12:17:36 CEST)
|
|
Share this article with
×
Cosmological models with linearly varying deceleration parameter in the cosmological theory based on Lyra’s geometry have been discussed. Exact solutions have been obtained for a spatially flat FRW model by considering a time dependent displacement field. We have also obtained the time periods during which the universe undergoes decelerated and accelerated expansions for a matter-dominated universe.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; weak measurement; transition probability amplitude; atomic metastable states
Online: 29 April 2018 (10:01:25 CEST)
|
|
Share this article with
×
A method for measuring the real part of the weak value of spin for non-zero rest mass atoms is presented using a variant on the original Stern-Gerlach apparatus. The experiment utilises helium in the metastable 23S1 state. A full simulation for observing the real part of the weak value using the impulsive approximation has been carried out and it predicts a displacement of the beam, Δw, that is within the resolution of our detector. It also indicates how this shift might be increased. The full analysis also indicated that there is a limit, L, to the applicability of the weak value approximation and has been evaluated for our apparatus. This experiment has the possibility to be expanded to utilise other nobal gas species such as neon and argon in the 3P2 metastable state, but we shall restrict this paper to metastable helium only.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; surface plasmons; time crystal; thin film
Online: 29 April 2018 (09:26:31 CEST)
|
|
Share this article with
×
The influence of the film thickness and the substrate’s refractive index on the surface mode at the superstrate is an important study step that may help clearing some of the misunderstandings surrounding their propagation mechanism. A single sub-wavelength slit perforating a thin metallic film is among the simplest nanostructure capable of launching Surface Plasmon Polaritons on its surrounding surface when excited by an incident field. Here, the impact of the substrate and the film thickness on surface waves is investigated. When the thickness of the film is comparable to its skin depth, SPP waves from the substrate penetrate the film and emerge from the superstrate, creating a superposition of two SPP waves, that leads to a beat interference envelope with well-defined loci which are the function of both the drive frequency and the dielectric constant of the substrate/superstrate. As the film thickness is reduced to the SPP’s penetration depth, surface waves from optically denser dielectric/metal interface would dominate, leading to volume plasmons that propagate inside the film at optical frequencies. Interference of periodic volume charge density with the incident field over the film creates charge bundles that are periodic in space and time.
Preprint
|
|
|
Physical Sciences, Optics; surface plasmon resonance; biosensing; nanofabrication; lab-on-a-chip; microfluidic
Online: 27 April 2018 (16:06:58 CEST)
|
|
Share this article with
×
Surface Plasmon Resonance (SPR) based sensors have the advantage of being label-free, enzyme-free and real-time. However, their spreading in multidisciplinary research is still limited and almost confined to prism-coupled devices. Plasmonic gratings, combined with a simple and cost-effective instrumentation, have been poorly developed compared to prism-coupled system mainly due to their lower sensitivity. Here we describe the optimization and signal enhancement of a sensing platform based on phase-interrogation method, which entails the exploitation of a nanostructured sensor. This technique is particularly suitable for integration of the plasmonic sensor in a lab-on-a-chip platform and can be used in a microfluidic circuit to ease the sensing procedures and limit the injected volume. The careful optimization of most suitable experimental parameters by numerical simulations leads to a 30 to 50% enhancement of SPR response, opening new possibilities for applications in the biomedical research field while maintaining the ease and versatility of the configuration.
Preprint
|
|
|
Physical Sciences, Mathematical Physics; dark energy; dark matter; cosmic microwave background; large numbers hypothesis; varying fundamental constants; symmetry
Online: 27 April 2018 (06:01:12 CEST)
|
|
Share this article with
×
Recent observations of the dark energy density demonstrates the fine-tuning problem and challenges in theoretical modelling. In this study, we apply the self-similar symmetry (SSS) model, describing the hierarchical structure of the universe based on the Dirac large numbers hypothesis, to Einstein's cosmological term. We introduce a new similarity dimension, DB, in the SSS model. Using the DB SSS model, the cosmological constant, vacuum energy density, and Hubble parameter can be simply expressed as a function of the cosmic microwave background (CMB) temperature. We show that the initial value of the vacuum energy density at the creation of the universe is ρ0 = 1/8παf6, where αf is the fine structure constant. The results indicate that the CMB is the primary factor for the evolution of the universe, providing a unified understanding of the problems of naturalness.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; quantum gravity; emergent quantum mechanics; gravitational waves, general relativity
Online: 27 April 2018 (04:58:59 CEST)
|
|
Share this article with
×
Some physicists surmise that gravity lies outside of quantum mechanics. Thus theories like the standard semiclassical theory of quantum to gravity coupling (that of Rosenfeld and Møller) are possible real models of interaction, rather than a mere approximation of a theory of quantum gravity. Unfortunately, semiclassical gravity creates inconsistencies such as superluminal communication. Alternatives by authors such as Diósi, Martin, Penrose, and Wang often use the term 'stochastic' to set themselves apart from the standard semiclassical theory. These theories couple to fluctuations caused by for instance continuous spontaneous localization, hence the term 'stochastic'. This paper looks at stochastic gravity in the framework of a class of emergent or ontological quantum theories, such as those by Bohm, Cetto, and de Broglie. It is found that much or all of the trouble in connecting gravity with a microscopic system falls away, as Einstein's general relativity is free to react directly with the microscopic beables. The resulting continuous gravitational wave radiation by atomic and nuclear systems does not, in contrast to Einstein's speculation, cause catastrophic problems. The small amount of energy exchanged by gravitational waves may have measurable experimental consequences. A very recent experiment by Vinante et al. performed on a small cantilever at mK temperatures shows a surprising non-thermal noise component, the magnitude of which is consistent with the stochastic gravity coupling explored here.
Preprint
|
|
|
Physical Sciences, Particle & Field Physics; dipole-dipole interaction; unruh effect; quantum field theory in curved space
Online: 24 April 2018 (05:43:23 CEST)
|
|
Share this article with
×
We study the resonant dipole-dipole interaction energy between two uniformly accelerated identical atoms, one excited and the other in the ground state, prepared in a correlated Bell-type state, and interacting with the scalar field or the electromagnetic field nearby a perfectly reflecting plate. We suppose the two atoms moving with the same uniform acceleration, parallel to the plane boundary, and that their separation is constant during the motion. We separate the contributions of vacuum fluctuations and radiation reaction field to the resonance energy shift of the two-atom system, and show that Unruh thermal fluctuations do not affect the resonance interaction, which is exclusively related to the radiation reaction field. However, nonthermal effects of acceleration in the radiation-reaction contribution, beyond the Unruh acceleration-temperature equivalence, affect the resonance interaction energy. By considering specific geometric configurations of the two-atom system relative to the plate, we show that the presence of the mirror significantly modifies the resonance interaction energy between the two accelerated atoms. In particular, we find that new and different features appear with respect to the case of atoms in the free space, related to the presence of the boundary and to the peculiar structure of the quantum electromagnetic field vacuum in the locally inertial frame. Our results suggest the possibility to exploit the resonance interaction between accelerated atoms, as a probe for detecting the elusive effects of atomic acceleration on radiative processes.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Dirac 'trajectories'; Feynman paths; Weak values; Bohm approach.
Online: 18 April 2018 (14:29:26 CEST)
|
|
Share this article with
×
There has been a recent revival of interest in the notion of a `trajectory' of a quantum particle. In this paper we detail the relationship between Dirac's ideas, Feynman paths and the Bohm approach. The key to the relationship is the weak value of the momentum which Feynman calls a transition probability amplitude. With this identification we are able to conclude that a Bohm `trajectory' is the average of an ensemble of actual individual stochastic Feynman paths. This implies that they can be interpreted as the mean momentum flow of a set of individual quantum processes and not the path of an individual particle. This enables us to give a clearer account of the experimental two-slit results of Kocsis {\em et al.}}
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; quantum theory;time orientability;time reversal; topology of spacetime
Online: 18 April 2018 (12:38:01 CEST)
|
|
Share this article with
×
A number of experimental tests of time orientability are described as well as clear experimental signatures from non time orientability (time reversal). Some tests are well known, while others are based on more recent theoretical work. Surprisingly, the results all suggest that time is not orientable at a microscopic level; even definitive tests are positive. At a microscopic level the direction of time can reverse and a consistent forward time direction cannot be defined. That is the conclusion supported by a range of well-known experiments. The conflict between quantum theory and local realism; electrodynamics with electric charges; and spin half transformation properties of fermions; can all be interpreted as evidence of time reversal. While particle-antiparticle annihilation provides a definitive test. It offers both a new view of space-time and an novel interpretation of quantum theory with the potential to unify classical and quantum theories.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; planetary nebulae: general;
stars: AGB and post-AGB;
stars: variables: general;
stars: winds, outflows
Online: 16 April 2018 (14:05:31 CEST)
|
|
Share this article with
×
I review some aspects related to the influence of planets on the evolution of stars before and beyond the main sequence. Some processes include the tidal destruction of a planet on to a very young main sequence star, on to a low mass main sequence star, and on to a brown dwarf. This process releases gravitational energy that might be observed as a faint intermediate luminosity optical transient (ILOT) event. I then summarize the view that some elliptical planetary nebulae are shaped by planets. When the planet interacts with a low mass upper asymptotic giant branch (AGB) star it both enhances the mass loss rate and shapes the wind to form an elliptical planetary nebula, mainly by spinning up the envelope and by exciting waves in the envelope. If no interaction with a companion, stellar or sub-stellar, takes place beyond the main sequence, the star is termed a Jsolated star, and its mass loss rates on the giant branches are likely to be much lower than what is traditionally assumed.
Preprint
|
|
|
Physical Sciences, Optics; Raman microspectroscopy; optical tweezers; optofluidics; E. coli; antibiotics
Online: 12 April 2018 (08:37:01 CEST)
|
|
Share this article with
×
Analyzing the cells in various body fluids can greatly deepen the understanding of the mechanisms governing the cellular physiology. Because of the variability of physiological and metabolic states, it is important to be able to perform such studies on individual cells. Therefore, we developed an optofluidic system in which we precisely manipulated and monitored individual cells of Escherichia coli. We used laser tweezers Raman spectroscopy (LTRS) in a microchamber chip to manipulate and analyze individual E. coli cells. We subjected the cells to antibiotic cefotaxime, and we observed the changes by the time-lapse microscopy and Raman spectroscopy. We found observable changes in the cellular morphology (cell elongation) and in Raman spectra, which were consistent with other recently published observations. We tested the capabilities of the optofluidic system and found it to be a reliable and versatile solution for this class of microbiological experiments.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; Spatially resolved ARPES; 2D materials; Band structure; Graphene; Transition metal dichalcogenides; 2D heterostructures
Online: 11 April 2018 (13:43:50 CEST)
|
|
Share this article with
×
In this paper a perspective on the application of spatially- and Angle- Resolved PhotoEmission Spectroscopy (ARPES) for the study of two-dimensional (2D) materials is presented. ARPES allows the direct measurement of the electronic band structure of materials generating extremely useful insights into their electronic properties. The possibility to apply this technique to 2D materials is of paramount importance because these ultrathin layers are considered fundamental for future electronic, photonic and spintronic devices. In this review an overview of the technical aspects of spatially localized ARPES is given along with a description of the most advanced setups for laboratory and synchrotron-based equipment. This technique is sensitive to the lateral dimensions of the sample, therefore a discussion on the preparation methods of 2D material is presented. Some of the most interesting results obtained by ARPES are reported in three sections including: graphene, transition metal dichalcogenides (TMDCs) and 2D heterostructures. Graphene has played a key role in ARPES studies because it inspired the use of this technique with other 2D materials. TMDCs are presented for their peculiar transport, optical and spin properties. Finally, the section featuring heterostructures highlights a future direction for research into 2D material structures.
Preprint
|
|
|
Physical Sciences, Acoustics; modal wave-number spectrum; match mode; horizontal line array; moving source
Online: 11 April 2018 (12:42:57 CEST)
|
|
Share this article with
×
In this study, a matched-mode autoregressive source depth estimation method (MMAR) based on autoregressive (AR) wavenumber estimation is proposed for a moving source in shallow water waveguides. The signal original frequency and the environmental parameters, namely, the sound speed profile and bottom properties are known as a prior knowledge. The mode wavenumbers are estimated by the AR modal wavenumber spectrum. On the basis of the mode wavenumber estimation, the mode amplitudes can be estimated by the wavenumber spectrum that is obtained by generalized Hankel transform. The source depth estimation is determined by the peak of source depth function wherein the data mode best matches the replica mode that is calculated using a propagation model. Compared with other methods of moving source depth estimation, the proposed method exhibits a better performance in source depth estimation under low signal-to-noise ratio or the small range span. The selection of horizontal line array depth is illustrated by simulation and normal mode theory in details.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; symmetry; linear molecules; group theory; finite symmetry; point groups
Online: 11 April 2018 (08:07:38 CEST)
|
|
Share this article with
×
A numerical application of linear-molecule symmetry properties, described by the D∞h point group, is formulated in terms of lower-order symmetry groups Dnh with finite n. Character tables and irreducible representation transformation matrices are presented for Dnh groups with arbitrary n-values. These groups are subsequently used in the construction of symmetry-adapted ro-vibrational basis functions for solving the Schrödinger equations of linear molecules as part of the variational nuclear motion program TROVE. The TROVE symmetrisation procedure is based on a set of "reduced" vibrational eigenvalue problems with simplified Hamiltonians. The solutions of these eigenvalue problems have now been extended to include the classification of basis-set functions using ℓ, the eigenvalue (in units of ℏ) of the vibrational angular momentum operator . This facilitates the symmetry adaptation of the basis set functions in terms of the irreducible representations of Dnh. 12C2H2 is used as an example of a linear molecule of D∞h point group symmetry to illustrate the symmetrisation procedure.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; fluid dynamics; two phase flow; level set function; cylindrical coordinates; continuity equation
Online: 10 April 2018 (08:14:04 CEST)
|
|
Share this article with
×
A new formulation for a proposed solution to the 3D Navier-Stokes Equations in cylindrical co-ordinates coupled to the continuity and level set convection equation is presented in terms of an additive solution of the three principle directions in the radial, azimuthal and z directions of flow and a connection between the level set function and composite velocity vector for the additive solution is shown. For the case of a vertical tube configuration with small inclination angle, results are obtained for the level set function defining the interface in both the radial and azimuthal directions. It is found that the curvature dependent part of the problem alone induces sinusoidal azimuthal interfacial waves wheras when the curvature is small oscillating radial interfacial waves occur. The implications of two extremes indicate the importance of looking at the full equations including curvature.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; crystallographic symmetry classifications; geometric Akaike Information Criteria; Akaike weights; multi-model inference; information theory
Online: 7 April 2018 (11:47:31 CEST)
|
|
Share this article with
×
Geometric Akaike Information Criteria (G-AICs) for generalized noise-level dependent crystallographic symmetry classifications of two-dimensional (2D) images that are more or less periodic in either two or one dimensions as well as Akaike weights for multi-model inferences and predictions are reviewed. Such novel classifications do not refer to a single crystallographic symmetry class exclusively in a qualitative and definitive way. Instead, they are quantitative, spread over a range of crystallographic symmetry classes, and provide opportunities for inferences from all classes (within the range) simultaneously. The novel classifications are based on information theory and depend only on information that has been extracted from the images themselves by means of maximal likelihood approaches so that these classifications are objective. This is in stark contrast to the common practice whereby arbitrarily set thresholds or null hypothesis tests are employed to force crystallographic symmetry classifications into apparently definitive/exclusive states, while the geometric feature extraction results on which they depend are never definitive in the presence of generalized noise, i.e. in all real world applications. Thus, there is unnecessary subjectivity in the currently practiced ways of making crystallographic symmetry classifications, which can be overcome by the approach outlined in this review.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; Belite, Hydration, Density Functional Theory, Water Adsorption, Calcium Silicate
Online: 6 April 2018 (15:24:22 CEST)
|
|
Share this article with
×
β-dicalcium silicate (β-Ca2SiO4, or β-C2S in cement chemistry notation) is one of the most important minerals in cement. An improvement of its hydration speed would be the key point for developing environmentally friendly cements with lower energy consumption and CO2 emissions. However, there is a lack of fundamental understanding on the water/β-C2S surface interactions. Therefore, in this work we aim to understand the water adsorption and dissociation mechanism on the β-C2S (100) surface using density functional theory (DFT) calculations. Our results indicate that thermodynamically favorable water adsorption process takes place in several surface sites, with a broad range of adsorption energies (-0.78 to -1.24 eV), depending on the particular water conformation and surface site. To clarify the key factor governing the adsorption, the electronic properties of water at the surface sites were analyzed. The partial density of states (DOS), charge analysis, and electron density difference analyses suggest a dual interaction of water with β-C2S (100) surface: a nucleophilic interaction of the water oxygen lone pair with surface calcium atoms, and an electrophilic interaction (hydrogen bond) of one water hydrogen with surface oxygen atoms, being the first one the stronger interaction. Hence, we suggest that β-C2S hydration could be enhanced by introducing chemical or structural changes that increase both the electronegative/positive character of the surface.
Preprint
|
|
|
Physical Sciences, Optics; Quantitative phase microscopy; Digital holographic microscopy; lensless microscopy; resolution enhancement; space-bandwidth product
Online: 30 March 2018 (14:09:57 CEST)
|
|
Share this article with
×
Quantitative phase microscopy (QPM), a technique combining phase imaging and microscopy, enables visualization of the 3-D topography in reflective samples as well as the inner structure or refractive index distribution of transparent and translucent samples. However, as in conventional optical microscopy, QPM provides either a large field of view (FOV) or a high resolution but not both. Many approaches such as oblique illumination, structured illumination and speckle illumination have been proposed to improve the spatial resolution of phase microscopy by restricting other degrees of freedom (mostly time). Therefore, the space bandwidth product (SBP) of QPM becomes enlarged. This paper aims to provide an up-to-date review on the resolution enhancement approaches of QPM, discussing the pros and cons of each technique as well as the confusion on resolution definition claim on QPM and other coherent microscopy.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; quantum ontology; sub-quantum dynamics; micro-constituents; emergent space-time; emergent quantum gravity; entropic gravity; black hole thermodynamics
Online: 30 March 2018 (05:57:25 CEST)
|
|
Share this article with
×
In this work it is acknowledged that important attempts to devise an emergent quantum (gravity) theory require space-time to be discretized at the Planck scale. It is therefore conjectured that reality is identical to a sub-quantum dynamics of ontological micro-constituents that are connected by a single interaction law. To arrive at a complex system-based toy-model identification of these micro-constituents, two strategies are combined. First, by seeing gravity as an entropic phenomenon and generalizing the dimensional reduction of the associated holographic principle, the universal constants of free space are related to assumed attributes of the micro-constituents. Second, as the effective field dynamics of the micro-constituents must eventually obey Einstein’s field equations, a sub-quantum interaction law is derived from a solution of these equations. A Planck-scale origin for thermodynamic black hole characteristics and novel views on entropic gravity theory result from this approach, which eventually provides a different view on quantum gravity and its unification with the fundamental forces.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Measurement-Device-Independent Quantum Key Distribution; Quantum Optics; Two-Photon Interference
Online: 27 March 2018 (15:24:03 CEST)
|
|
Share this article with
×
Measurement-Device-Independent Quantum Key Distribution (MDI-QKD) is a two-photon protocol devised to eliminate eavesdropping attacks that interrogate or control the detector in realized quantum key distribution systems. In MDI-QKD, the measurements are carried out by an untrusted third party, and the measurement results are announced openly. Knowledge or control of the measurement results gives the third party no information about the secret key. Error-free implementation of the MDI-QKD protocol requires the crypto-communicating parties, Alice and Bob, to independently prepare and transmit single photons that are physically indistinguishable, with the possible exception of their polarization states. In this paper, we apply the formalism of quantum optics and Monte Carlo simulations to quantify the impact of small errors in wavelength, bandwidth, polarization and timing between Alice's photons and Bob's photons on the MDI-QKD quantum bit error rate (QBER). Using published single-photon source characteristics from two-photon interference experiments as a test case, our simulations predict that the finite tolerances of these sources contribute (4.04+/-20/Nsifted) to the QBER in an MDI-QKD implementation generating an Nsifted-bit sifted key.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; fully kinetic ions; ion temperature gradient instabilities; tokamak; gyrokinetics; particle-in-cell
Online: 27 March 2018 (06:03:12 CEST)
|
|
Share this article with
×
The feasibility of using full ion kinetics, instead of gyrokinetics, in simulating low-frequency Ion-Temperature-Gradient (ITG) instabilities in tokamaks has recently been demonstrated by Sturdevant et al. [Physics of Plasmas 24, 081207 (2017)]. In that work, a variational integrator was developed to integrate the full orbits of ions in toroidal geometry, which proved to be accurate in capturing both the short-time scale cyclotron motion and long time scale drift motion. The present work extends that work in three aspects. First, we implement a relatively simple full orbit integrator, the Boris integrator, and demonstrate that the accuracy of this integrator is also sufficient for simulation of ITG instabilities. Second, the equilibrium magnetic configuration is extended to general toroidal configuration specified numerically, enabling simulation of realistic equilibria reconstructed from tokamak experiments. Third, we extend that work to the nonlinear regime and investigate the nonlinear saturation of ITG instabilities. To verify the new numerical implementation of the orbit integrator and magnetic configuration, the linear electrostatic ITG frequency and growth rate are compared with those given in Sturdevant's work and good agreement is found.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; numerical relativity; many-core architectures; Knight Landing; vectorization
Online: 26 March 2018 (07:53:06 CEST)
|
|
Share this article with
×
A simple optimization strategy for the computation of 3D finite-differencing kernels on many-cores architectures is proposed. The 3D finite-differencing computation is split direction-by-direction and exploits two level of parallelism: in-core vectorization and multi-threads shared-memory parallelization. The main application of this method is to accelerate the high-order stencil computations in numerical relativity codes.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; DNA; DNA nanotechnology; patchy particles; Wertheim theory; thermodynamic integration; phase coexistence
Online: 25 March 2018 (16:14:27 CEST)
|
|
Share this article with
×
We present a numerical study in which large-scale bulk simulations of self-assembled DNA constructs have been carried out with a realistic coarse-grained model. The investigation aims at obtaining a precise, albeit numerically demanding, estimate of the free energy for such systems. We then, in turn, use these accurate results to validate a recently proposed theoretical approach that builds on a liquid-state theory, the Wertheim theory, to compute the phase diagram of all-DNA fluids. This hybrid theoretical/numerical approach, based on the lowest order virial expansion and a nearest-neighbor DNA model, can provide, in an undemanding way, a thermodynamic description of DNA associating fluids that is in semi-quantitative agreement with experiments. We show that the predictions of such scheme are as accurate as the ones obtained with more sophisticated methods. We also demonstrate the flexibility of the approach by incorporating non-trivial additional contributions that go beyond the nearest-neighbor model to compute the DNA hybridization free energy.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; cosmological constant problem; non-linear sigma model; quantum gravity
Online: 19 March 2018 (10:33:12 CET)
|
|
Share this article with
×
We generalize the idea of quantum clock time to quantum spacetime reference frame via physical realization of a reference system by quantum rulers and clocks. Omitting the internal degrees of freedom (such as spins) of the physical rulers and clocks, only considering their metric properties, the spacetime reference frame is described by a bosonic non-linear sigma model (NLSM). We study the quantum behavior of the system under approximations, and obtain (1) a cosmological constant valued (2/π)ρc0 (ρc0 the critical density at near current epoch) which is very close to the observations; (2) an effective Einstein-Hilbert term; (3) the ratio of variance to mean-squared of spacetime interval tends to a universal constant 2/π in the infrared region. This effect is testable by observing a linear dependence between the inherent quantum variance and mean-squared of the redshifts from cosmic distant spectral lines. The proportionality is expected to be the observed percentage of the dark energy. The equivalence principle is also generalized to the quantum level.
Preprint
|
|
|
Physical Sciences, Other; aptamer; aptasensor; electrical properties; networks; proteotronics
Online: 16 March 2018 (11:12:17 CET)
|
|
Share this article with
×
Selected by in vitro techniques (SELEX, cell-SELEX), aptamers are strands of DNA or RNA molecules able to bind a wide range of targets, from small molecules to live cells, and even tissues, with high affinity and specificity. Due to their efficient targeting ability, aptamers are extensively used in different fields of applications. For example, they ensure high performance as cancer-related markers or in recognizing cancer cells. Actually, they represent a promising way for early diagnosis (biosensors) and to deliver imaging agents and drugs, in both cancer imaging and therapy (therapeutic aptamers). Aptamer-based biosensors (aptasensors) have attracted particular attention over the last decades, so as the possibility of using aptamers in disease therapy in substitution of monoclonal antibodies. The paper briefly reviews the most recent literature on this topic, both concerning the advances in biomedical applications and in the development of electrical aptasensors. The investigation concerning the bioelectronics features of aptamers, to be implemented in the development of electrical nanobiosensors, is also reviewed. To this aim, some recent results of a theoretical/computational framework for modelling the electrical properties of biomolecules (Proteotronics) are reported.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; atomic layer deposition; ZnO; ideality factor; series resistance; Schottky photodetector
Online: 16 March 2018 (04:58:13 CET)
|
|
Share this article with
×
We report on the fabrication and electrical characteristics of zinc-oxide (ZnO) based metal-insulator-semiconductor (MIS) type Schottky barrier diodes (SBHs). ZnO thin layer on the p-type silicon substrate was fabricated by atomic layer deposition (ALD). The structure and surface properties of the thin film were characterized by X-ray diffraction (XRD), atomic force microscope (AFM) and secondary ion mass spectrometer (SIMS). The current-voltage (I-V) characteristics of Al/ALD-grown ZnO/p-Si diodes were measured under dark at room temperature. The electrical parameters such as ideality factor (n), series resistance (Rs) and barrier height (ϕb) of the diodes were analyzed using standard thermionic emission (TE) theory, Norde and Cheung method. The barrier height value obtained from I-V and Cheung method was found to be 0.73 eV and 0.76 eV, respectively. The interface state density (Dit) of the diodes was determined from the I-V characteristics. The nonideal behavior of measured parameters suggested the presence of interface states. The obtained results showed that the prepared diode can be used for NIR Schottky photodetector applications.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; atomic structure; hartree fock; exchange; line broadening; scattering
Online: 8 March 2018 (02:10:55 CET)
|
|
Share this article with
×
Atomic structure of N-electron atoms is often determined using the Hartree-Fock method, which is an integro-differential equation. The exchange term of the Hartree-Fock equations is usually treated as an inhomogeneous term of a differential equation, or with a local density approximation. This work uses matrix methods to solve for the Hartree-Fock equations, rather than the more commonly-used shooting method to integrate an inhomogeneous differential equation. It is well known that a derivative operator can be expressed as a matrix made of finite-difference coefficients; energy eigenvalues and eigenvectors can be obtained by using computer linear-algebra packages. We extend the same technique to integro-differential equations, where a discretized integral can be written as a sum in matrix form. This method is compared against experiment and standard atomic structure calculations. We also can use this method for free-electron wavefunctions. This technique is important for spectral line broadening in two ways: improving the atomic structure calculations, and improving the motion of the plasma electrons that collide with the atom.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; Stark broadening; van der Waals broadening; line shapes; helium plasma; corona discharge; plasma diagnostics; code comparison; neutral broadening; pressure broadening
Online: 7 March 2018 (13:36:47 CET)
|
|
Share this article with
×
Passive plasma spectroscopy is a well-established non-intrusive diagnostic technique. Depending on the emitter and its environment which determine the dominant interactions and effects governing emission line shapes, passive spectroscopy allows the determination of electron densities, emitter and perturber temperatures as well as other quantities like abundances. However, using spectroscopy needs appropriate line shape codes retaining all the physical effects governing the emission line profiles. This requires for line shape code developers to continuously correct or improve them to increase their accuracy when applied for diagnostics. This is exactly the aim expected from code-code and code-data comparisons. In this context, the He I 492 nm emitted in a helium corona discharge at room temperature represents an ideal case since its profile results from several broadening mechanisms: Stark, Doppler, resonance and van der Waals. The importance of each broadening mechanism depends on the plasma parameters. Here the profiles of the He I 492 nm in a helium plasma computed by various codes are compared for a selected set of plasma parameters. In addition, preliminary results related to plasma parameter determination using experimental spectra from a helium corona discharge at low pressure 1- 2 bars, are presented.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; stark broadening; van der waals broadening; line shapes; helium plasma; corona discharge; plasma diagnostics; code comparison; neutral broadening; pressure broadening
Online: 6 March 2018 (03:51:17 CET)
|
|
Share this article with
×
Many spectroscopic diagnostics are routinely used as a technique to infer the plasma parameters from line emission spectra but their accuracy depends on the numerical model or code used for the fitting process. However, the validation of a line shape code requires some steps : comparison of the line shape code with other similar codes for some academic (simple) cases and then more complex ones, comparison of the fitting parameters obtained from the best fit of the experimental spectra with those obtained with other diagnostic techniques and/or comparison of the fitting parameters obtained by different codes to fit the same experimental data. Here we compare the profiles of the hydrogen Balmer β line in a helium plasma computed by six codes for a selected set of plasma parameters and we report on the plasma parameters inferred by each of them from the fitting to a number of experimental spectra measured in a helium corona discharge where the pressure was in the range 1- 5 bar.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Casimir effect, dispersion, ultraviolet divergences, infrared divergences
Online: 1 March 2018 (16:58:15 CET)
|
|
Share this article with
×
It is familiar that the Casimir self-energy of a homogeneous dielectric ball is divergent, although a finite self-energy can be extracted through second order in the deviation of the permittivity from the vacuum value. The exception occurs when the speed of light inside the spherical boundary is the same as that outside, so the self-energy of a perfectly conducting spherical shell is finite, as is the energy of a dielectric-diamagnetic sphere with $\varepsilon\mu=1$, a so-called isorefractive or diaphanous ball. Here we re-examine that example, and attempt to extend it to an electromagnetic $\delta$-function sphere, where the electric and magnetic couplings are equal and opposite. Unfortunately, although the energy expression is superficially ultraviolet finite, additional divergences appear that render it difficult to extract a meaningful result in general, but some limited results are presented.
Preprint
|
|
|
Physical Sciences, Atomic & Molecular Physics; Plasma spectroscopy; Line broadening; Series limit; Balmer lines; Inglis-Teller limit; line merging.
Online: 1 March 2018 (16:38:57 CET)
|
|
Share this article with
×
For a given set of plasma parameters, along a single series (Lyman, Balmer etc) the lines with higher
principal quantum number(n) lines get progressively wider, closer to each other,
and start merging for a certain critical n.
In the present work four different codes(with further options) are used to calculate the entire Balmer series for moderate and high electron densities. Particular attention is paid to the relevant physics, such as the cutoff criteria, strong and penetrating electron collisions.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; universe expansion; Hubble constant; cavity finesse; cosmological redshift; strain
Online: 27 February 2018 (03:41:54 CET)
|
|
Share this article with
×
We describe the effect of the expansion of space on the wavelength of the light beam in a Fabry-Pérot interferometer. For an instrument such as the Laser Interferometer Gravitational-Wave Observatory (LIGO), which has high sensitivity and a long period of light storage, the wavelength of laser photons are redshifted due to the expansion of space in each cavity by an amount given by , where is the Hubble constant and is the light storage time for the cavity. Since is based on the cavity finesse which depends on the laser beam full width at half maximum (FWHM) of each cavity, we show that a difference in finesses between the LIGO arm cavities produces a signal at the anti-symmetric output port given by where and are the beam FWHM at time t, respectively, for the X and Y arm cavities and is a beam proportionality constant to be determined expermentally. Assuming , then for cavity beams FWHM of the output signal has the range , which is detectable by advanced LIGO.
Preprint
|
|
|
Physical Sciences, Optics; optical metamaterials; fundamental concepts in photonics; light-matter interactions at the subwavelength and nanoscale; fundamental understanding of linear and nonlinear optical processes in novel metamaterials underpinning photonic devices and components; advancing the frontier of nanophotonics with the associated nanoscience and nanotechnology; nanostructures that can serve as building blocks for nano-optical systems; use of nanotechnology in photonics; nonlinear nanophotonics, plasmonics and excitonics; subwavelength components and negative index materials; slowing, store, and processing light pulses; materials with such capabilities that could be used for optical sensing, tunable optical delay lines, optical buffers, high extinction optical switches, novel image processing hardware, and highly-efficient wavelength converters
Online: 26 February 2018 (11:24:39 CET)
|
|
Share this article with
×
Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described which enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular properties of the outlined processes in the proposed metamaterial are demonstrated through numerical simulations. Potential applications include ultra-miniature amplifiers, frequency changing reflectors, modulators, pulse shapers, and remotely actuated sensors.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; Dirac electron; charge order; optical conductivity; organic conductor; α-(BEDT-TTF)2I3
Online: 26 February 2018 (10:39:40 CET)
|
|
Share this article with
×
The optical conductivity in the charge order phase is calculated in the extended Hubbard model describing an organic Dirac electron system α-(BEDT-TTF)2I3 using the mean field theory and the Nakano-Kubo formula. A peak structure due to interband excitation being characteristic in two-dimensional Dirac electron system is found above the charge order gap. It is shown that the peak structure originates from the Van Hove singularities of the conduction and valence bands, where those singularities are located at a saddle point between two Dirac cones in momentum space. The frequency of the peak structure exhibits drastic change in the vicinity of the charge order transition.
Preprint
|
|
|
Physical Sciences, Optics; biophotonic; Terahertz; time domain spectroscopy; absorption enhancement; laser cutting
Online: 26 February 2018 (09:30:06 CET)
|
|
Share this article with
×
In biology molecules and macromolecules like sugars, proteins, DNA, and RNA are of utter importance. Detecting their presence as well as their conformation is still a challenge in many cases. It is well known that the vibrational states of such molecules lie from the infrared to the TeraHertz range. Spectroscopy can be used to detect such compounds and probe their conformation. Still, terahertz spectroscopy on biosample is a challenge for two main reasons: water absorption; and the small size of the samples. The sample volume is smaller than the cube of the TeraHertz wavelength; the light matter interactions are thus extremely reduced. In this paper, we present the design, fabrication, characterization and the first typical uses of a biophotonic device aiming at increasing light matter interaction to enable terahertz spectroscopy of minute samples on a broad band (0.2–2 THz). We demonstrate time domain spectroscopy experiments on few µl samples showing the validity of our approach.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; Quantum Gravity; Gravitational Lensing; Dark Matter; Quantum Vacuum; Graviton
Online: 14 February 2018 (11:57:57 CET)
|
|
Share this article with
×
We report the use of Einstein rings to reveal the quantized and dynamical states of space-time in a region of impressed gravitational field as predicted by the Nexus Paradigm of quantum gravity. This in turn reveals the orbital speeds of objects found therein and the radius of curvature of the quantized space-time. Similarities between the Nexus graviton and the singular isothermal sphere (SIS) in the Cold Dark Matter (CDM) paradigm are highlighted. However unlike the singular isothermal sphere, the Nexus graviton does not contain singularities or divergent integrals. This solves the core cusp problem. In this work, data from a sample of fifteen Einstein rings published on the Cfa-Arizona Space Telescope Lens Survey (CASTLES) website is used to probe the quantized properties of space-time.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; cosmology; dark Matter; early universe
Online: 11 February 2018 (07:11:20 CET)
|
|
Share this article with
×
Understanding the nature of the Dark Matter (DM) is one of the current challenges in modern astrophysics and cosmology. Knowing the properties of the DM particle would shed light on physics beyond the Standard Model and even provide us with details of the early Universe. In fact, the detection of such a relic would bring us information from the pre-Big Bang Nucleosynthesis (BBN) period, an epoch from which we have no data, and could even hint at inflationary physics. In this work, we assume that the expansion rate of the Universe after inflationary is governed by the kinetic energy of a scalar field ϕ, in the so-called “kination” model. We assume that the ϕ field decays into both radiation and DM particles, which we take to be Weakly Interacting Massive Particles (WIMPs). The present abundance of WIMPs is then fixed during the kination period through either a thermal “freeze-out” or “freeze-in” mechanism, or through a non-thermal process governed by the decay of ϕ. We explore the parameter space of this theory with the requirement that the present WIMP abundance provides the correct DM relic budget. Requiring that BBN occurs during the standard cosmological scenario sets a limit on the temperature at which the kination period ends. Using this limit and assuming the WIMP has a mass mχ = 100 GeV, we obtain that the thermally-averaged WIMP annihilation cross section has to satisfy the constraints 3.5 × 10−16 GeV−2 ≲ (σv) ≲ 1.4 × 10−5 GeV−2 in order for having at least one of the production mechanism to yield the observed amount of DM. This result shows how the properties of the WIMP particle, if ever measured, can yield information on the pre-BBN content of the Universe.
Preprint
|
|
|
Physical Sciences, Other; abduction; recursion; physical law; Hume’s problem
Online: 11 February 2018 (04:35:28 CET)
|
|
Share this article with
×
The paper studies some cases in physics such as Galilean inertia motion and etc., and presents a logical schema of recursive abduction, from which we can derive the universality of physical laws in an effective logical path without requiring infinite inductions. Recursive abduction provides an effective logical framework to connect a universal physical law with finite empirical observations based on both quasi-law tautologies and suitable recursive dimensions, two new concepts introduced in this paper. Under the viewpoint of recursive abduction, the historical difficulty from Hume’s problem naturally vanishes. In Hume’s problem one always misunderstood a time-recursive issue as an infinitely inductive problem and, thus, sank into an inescapable quagmire. With this new effective logical schema, the paper gives a concluding discussion to Hume’s problem and justifies the validity of probability argument for natural laws.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; transition metal dichalcogenides; MoS2; field effect transistor; field emission
Online: 11 February 2018 (04:25:10 CET)
|
|
Share this article with
×
We report the electrical characterization and the field emission properties of CVD-grown MoS2 bilayers deposited on SiO2/Si substrate. Current-voltage characteristics are measured in the back-gate transistor configuration, with Ti contacts patterned by electron beam lithography. We confirm the n-type character of as-grown MoS2 and we report normally-on field effect transistors. Local characterization of field emission is performed inside a scanning electron microscope chamber with piezo-controlled tungsten tips working as the anode and the cathode. We demonstrate that an electric field of ~200 V/μm is able to extract current from the flat part of MoS2 bilayers, which therefore can be conveniently exploited for field emission applications even in low field-enhancement configurations. We show that a Fowler-Nordheim model, modified to account for electron confinement in 2D materials, fully describes the emission process.
Preprint
|
|
|
Physical Sciences, Other; Quantum mechanics; superposition; collapse; bio-psychology; observation, mental representation; reality; potentiality; infinity; nothingness;
Online: 8 February 2018 (14:56:38 CET)
|
|
|
Share this article with
×
When phenomena in quantum mechanics are interpreted from the perspective of bio-psychology, wave function collapse from several to a single eigenstate must be plausibly explained. Quantum mechanics requires a context, yet the context of an observer is rarely considered. On the other hand, in bio-psychology, the observer context is examined to explain superposition and collapse by different mental functions used in everyday life. Three mental functions are described, one of which is responsible for observation, and the others for conservation and treatment of information in mental representation. Whereas observation produces information with certainty, the subsequent processes result in uncertain potentiality. In order to encompass uncertainty, multiple possibilities are simultaneously considered in mental superposition, one of which should represent the unknown future outcome. During observation, all suggested potentialities necessarily collapse to one real outcome. The collapse of superposition does not occur in observable physical reality, but in its mental representation. Some physical principles—such as superposition, infinity and nothingness before the Big Bang—are pure phenomena of mental representation, which will always remain unverifiable by observation. This argument proves that mental representation brought about by the observer context participates in the production of mental models for the best approximation of physical reality.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; X-rays; polarimetry; general; history of astronomy
Online: 7 February 2018 (10:35:37 CET)
|
|
Share this article with
×
Astronomical X-ray polarimetry was first explored in the end of the 60's by pioneering rocket instruments. The craze arising from the first discoveries on stellar and supernova remnant X-ray polarization led to the addition of X-ray polarimeters on-board of early satellites. Unfortunately, the inadequacy of the diffraction and scattering technologies required to measure polarization with respect to the constraints driven by X-ray mirrors and detectors, coupled to long integration times, slowed down the field for almost 40 years. Thanks to the development of new, highly sensitive, compact X-ray polarimeters in the beginning of the 2000's, the possibility to observe astronomical X-ray polarization is rising again and scientists are now ready to explore the high energy sky thanks to modern X-ray polarimeters. In the forthcoming years, several X-ray missions (both rockets, balloons and satellites) will open a new observational windows. A wind of renewal blows over the area of X-ray polarimetry and this paper presents for the first time a quantitative assessment, all based on scientific literature, of the growth of interest for astronomical X-ray polarimetry.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; elliptical vortex; linear flow; Kida vortex; Stokes' theorem; Ball's theorem; moment of inertia; matrix basis
Online: 6 February 2018 (06:42:11 CET)
|
|
Share this article with
×
A four-parameter kinematic model for the position of a fluid parcel in a time-varying ellipse is introduced. For any ellipse advected by an arbitrary linear two-dimensional flow, the rates of change of the ellipse parameters are uniquely determined by the four parameters of the velocity gradient matrix, and vice-versa. This result, termed ellipse/flow equivalence, provides a stronger version of the well-known result that a linear velocity field maps an ellipse into another ellipse. Moreover, ellipse/flow equivalence is shown to be a manifestation of Stokes' theorem. This is done by deriving a matrix-valued relationship, called the geometric Stokes' theorem, that involves a spatial integral over the velocity gradient tensor, thus accounting for the two strain terms in addition to the divergence and vorticity. General expressions for various physical properties of an elliptical ring of fluid are also derived. The ellipse kinetic energy is found to be composed of three portions, associated respectively with the circulation, the rate of change of the moment of inertia, and the variance of parcel angular velocity around the ellipse. A particular innovation is the use of four matrices, termed the IJKL basis, that greatly facilitate the required calculations.
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; Brinkman type fluid; Fourier Integral transformation; side walls; oscillating shear stress
Online: 5 February 2018 (11:43:42 CET)
|
|
Share this article with
×
In this paper Brinkman type fluid over an infinite plate between side walls is being investigated. The flow is generated by oscillating shear stress of the bottom plate and the solutions are obtained by using Fourier integral transformation. The obtained results are presented in steady and transient states for both sin and cos shear stresses. The general solutions are reduced to some special cases corresponding, namely to the Brinkman type fluid over an infinite plate and flow of a Newtonian viscous fluid. Graphical illustrations are carried out to have in depth analysis of the involved physical parameters
Preprint
|
|
|
Physical Sciences, Fluids & Plasmas; Tank drainage; Power law MHD fluid; Analytical solution
Online: 5 February 2018 (11:41:11 CET)
|
|
|
Share this article with
×
This paper investigates the tank drainage problem of an isothermal, unsteady, incompressible electrically conducting Power law fluid. Analytic solution have been obtained from governing continuity and momentum equations subject to appropriate boundary conditions by using Perturbation method. The Power law fluid model solution without MHD is retrieved from this proposed model on substitution . Declaration on behalf of velocity profile, volume flux, average velocity, connection of time with respect to length of the tank and requirement of time for whole drainage of fluid are acquired. Special effects of numerous emerging parameter’s on velocity profile vz and depth of the fluid in the tank are graphically presented. Keywords: Tank drainage, Power law MHD fluid, Analytical solution.
Preprint
|
|
|
Physical Sciences, Acoustics; inverse acoustic problem; helicopter rotor; Ffowcs Williams and Hawkings equation; aerodynamic constraint; Thikhonov method
Online: 5 February 2018 (11:34:30 CET)
|
|
Share this article with
×
An inverse aeroacoustic problem for a helicopter rotor combined with aerodynamic constraint is proposed based on Ffowcs Williams and Hawkings equation in subsonic. The rotor noise includes thickness noise and loading noise when quadrupole noise is neglected. Thickness noise is related to geometry and motion conditions. Loading noise is related to the pressure on the wall. Therefore, the equation between pressure on the wall and far-field noise can be established, thus the pressure on the wall can be obtained by solving this equation. Since this equation is an ill-posed, the singular value decomposition combined with the regulation method is applied and the aerodynamic constraint is taken into account. The direct noise prediction is verify firstly and then the inverse problem is solved. The reconstruction pressure is compared to the input data. The result is in good agreement with the input value. At the same time, the influence of interference noise is also considered. Under low signal-to-noise ratio, the reconstruction result is also reasonable.
Preprint
|
|
|
Physical Sciences, Applied Physics; smartphone; magnetic hall sensor, magnetic field; lab physics; quadrupole
Online: 5 February 2018 (11:30:05 CET)
|
|
Share this article with
×
Current smartphones incorporate different types of sensors that allow us to know our spatial position, they give us information about pressure, speed, acceleration, time, acoustic level, and other different physical magnitudes. These smartphones measure each component of the magnetic field, bearing in mind that any current perpendicular to a magnetic field produces a small potential difference, transversal to the said current, being this voltage easily measurable by Hall sensors. With the implementation of three Hall sensors, and an appropriate app, we can measure the three components of the magnetic field vector, and with this we can obtain information and deduce properties of the physical systems considered. In this paper we are exploring the use of smartphones in a physics laboratory for freshman students. To do this, we have measured, using Hall sensors, the magnetic field created by a linear quadrature, and we have obtained, first of all, its dependence on the distance between the quadrupole and the magnetic sensor. The second purpose of this work is to show that the laboratory is a powerful tool that increases the significant learning of freshman students through advanced technological tools.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Fourier Theory; Heisenberg Uncertainty Principle; Quantum Fourier Transform; Quantum Information Processing; Schrödinger equation; Spectral Analysis
Online: 28 January 2018 (17:35:55 CET)
|
|
Share this article with
×
A quantum time-dependent spectrum analysis, or simply, quantum spectral analysis (QSA) is presented in this work, and it’s based on Schrödinger’s equation. In the classical world, it is named frequency in time (FIT), which is used here as a complement of the traditional frequency-dependent spectral analysis based on Fourier theory. Besides, FIT is a metric which assesses the impact of the flanks of a signal on its frequency spectrum - not taken into account by Fourier theory and let alone in real time. Even more, and unlike all derived tools from Fourier Theory (i.e., continuous, discrete, fast, short-time, fractional and quantum Fourier Transform, as well as, Gabor) FIT has the following advantages, among others: a) compact support with excellent energy output treatment, b) low computational cost, O(N) for signals and O(N2) for images, c) it does not have phase uncertainties (i.e., indeterminate phase for a magnitude = 0) as in the case of Discrete and Fast Fourier Transform (DFT, FFT, respectively). Finally, we can apply QSA to a quantum signal, that is, to a qubit stream in order to analyze it spectrally.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; smartphone; magnetic sensor, magnetic field; lab physics; quadrupole
Online: 26 January 2018 (16:17:43 CET)
|
|
Share this article with
×
We believe that a natural focus of the Physics Education Research community is on understanding and improving student learning in our physics courses. For this purpose, we are introducing smartphones in the physics laboratory. Current smartphones measure each component of the magnetic field, bearing in mind that any current perpendicular to a magnetic field produces a small potential difference, transversal to the said current, being this voltage easily measurable by Hall sensors. In this work, we have considered the magnetic field created by a linear quadrupole and we have studied its dependence on distance. Using an experimental procedure that is simple we have measured the magnetic field using the Hall sensor that most smartphones have, together with the corresponding app. The purpose of this work is to show that the laboratory is a powerful tool that increases significant learning under three conditions: 1) the practice must not be too sophisticated; 2) students must handle objects in the lab; and 3) the practice must be scientifically accurate, including the adjustments by minimum squares, and the following and necessary error calculation.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; The Big Bang concept; history of modern cosmology; singularity theorems; cosmological singularities in modified gravity models.
Online: 26 January 2018 (06:44:23 CET)
|
|
Share this article with
×
The first part of this paper contains a brief description of the beginnings of modern cosmology, which, the author will argue, was most likely born in the Year 1912. Some of the pieces of evidence presented here have emerged from recent research in the history of science, and are not usually shared with the general audiences in popular science books. Then, the important issue of the formulation of the original Big Bang concept, in the exact words of Fred Hoyle, is discussed. Too often, this is very deficiently explained (when not just misleadingly) in most of the available generalist literature. Other frequent uses of the same words, Big Bang, as to name the initial singularity of the cosmos, and also whole cosmological models, are then addressed, as evolutions of its original meaning. Quantum and inflationary additions to the celebrated singularity theorems by Penrose, Geroch, Hawking and others led to subsequent results by Borde, Guth and Vilenkin. And corresponding corrections to the Einstein field equations have originated, in particular, R2, f(R), and scalar-tensor gravities, giving rise to a plethora of new singularities. For completeness, an updated table with a classification of the same is given.
Preprint
|
|
|
Physical Sciences, Other; magnetic nanoparticles; ion channels; viscoelastic effects and anomalous diffusion; non-exponential statistics; influence of weak magnetic fields on living systems
Online: 26 January 2018 (05:11:59 CET)
|
|
Share this article with
×
Magnetic nanoparticles are met across many biological species ranging from magnetosensitive bacteria, fishes, bees, bats, rats, birds, to humans. They can be both of biogenetic origin and due to environmental contamination, being either in paramagnetic or ferromagnetic state. The energy of such naturally occurring single-domain magnetic nanoparticles can reach up to 10-20 room kBT in the magnetic field of the Earth, which naturally led to supposition that they can serve as sensory elements in various animals. This work explores within a stochastic modeling framework a fascinating hypothesis of magnetosensitive ion channels with magnetic nanoparticles serving as sensory elements, especially, how realistic it is given a highly dissipative viscoelastic interior of living cells and typical sizes of nanoparticles possibly involved.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; current-quark masses; Helmholtz equation; roots of Bessel and Neumann functions
Online: 16 January 2018 (13:20:36 CET)
|
|
Share this article with
×
Current-quark masses are compared to the rest masses allowed by the Helmholtz equation in a polar model. Within the uncertainty of the current u quark mass determination, the current quark mass coincides with the rest mass allowed by the Helmholtz equation in the polar model in accordance with the second root of the zero Neumann function. Current d quark mass coincides with the rest mass calculated in accordance with the third root of the Bessel zero function. On the basis of a comparison of these results with the results obtained earlier for ordinary real particles u and d quarks stability is discussed.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; Maximally multiqubit entangled state; Bell-pair state; CNOT gates
Online: 12 January 2018 (17:19:05 CET)
|
|
Share this article with
×
We propose a novel protocol to build a maximally entangled state based on controlled-not (CNOT) gates. In particular, we give detailed steps to construct maximally entangled state for 4-, 5-, and 6-qubit systems. The advantage of our method is the simple algebraic structure which can be realized via current experimental technology.
Preprint
|
|
|
Physical Sciences, Other; complexity; disequilibrium; equilibrium; individual information; informational entropy
Online: 11 January 2018 (05:31:00 CET)
|
|
Share this article with
×
This work is a generalization of the Lopez-Ruiz, Mancini and Calbet (LMC); and Shiner, Davison and Landsberg (SDL) complexity measures, considering that the state of a system or process is represented by a dynamical variable during a certain time interval. As the two complexity measures are based on the calculation of informational entropy, an equivalent information source is defined and, as time passes, the individual information associated to the measured parameter is the seed to calculate instantaneous LMC and SDL measures. To show how the methodology works, an example with economic data is presented.
Preprint
|
|
|
Physical Sciences, Astronomy & Astrophysics; Cosmological Constant; MOND; dark matter; dark energy; Lamda-CDM model
Online: 10 January 2018 (10:29:21 CET)
|
|
Share this article with
×
In this article a two-parameter model is developed for the universe. The two parameters are the age of the universe and Milgrom’s acceleration constant. It is shown that these are sufficient to calculate the amounts of matter and dark energy in the universe, as well as the contributions of dark matter and baryonic matter in the matter part. All this, not only for present time, but also as a function of cosmological time. The developed theory gives an adequate explanation for the phenomena of the accelerated scaling of the universe and the anomaly of the stellar rotation curves in galaxies. The numerical results are in agreement with those of the Lamda-CDM model.
Preprint
|
|
|
Physical Sciences, Condensed Matter Physics; wolframite, high-pressure, phase transitions, crystal structure, phonons, band structure.
Online: 8 January 2018 (18:22:35 CET)
|
|
Share this article with
×
In this article we review the advances that have been made on the understanding of the high-pressure structural, vibrational, and electronic properties of wolframite-type oxides since the first works in the early 1990s. Mainly tungstates, which are the best known wolframites, but also tantalates and niobates, with an isomorphic ambient-pressure wolframite structure, have been included in this review. Apart from estimating the bulk moduli of all known wolframites; the cation-oxygen bond distances and their change with pressure have been correlated with their compressibility. The composition variations of all wolframites have been employed to understand their different structural phase transitions to post-wolframite structures as a response to high pressure. The number of Raman modes and band gap energy changes have been also analyzed in the basis of these compositional differences. The reviewed results are relevant for both fundamental science and for the development of wolframites as scintillating detectors. The possible next research venues of wolframites have also been evaluated.
Preprint
|
|
|
Physical Sciences, General & Theoretical Physics; mesoscopic theory; internal variables; liquid crystals; damage parameter; dipolar media; flexible fibers
Online: 27 December 2017 (08:00:59 CET)
|
|
Share this article with
×
Internal and mesoscopic variables differ from each other fundamentally: both are state space variables, but mesoscopic variables are additional equipped with a distribution function introducing a statistical item into consideration which is missing in connection with internal variables. Thus, the alignment tensor of liquid crystal theory can be introduced as an internal variable or as one generated by a mesoscopic background using the microscopic director as mesoscopic variable. Because the mesoscopic variable is part of the state space, the corresponding balance equations change into mesoscopic balances, and additionally an evolution equation of the mesoscopic distribution function appears. The flexibility of the mesoscopic concept is not only demonstrated for liquid crystals, but is also discussed for dipolar media and flexible fibers.