Abstract: The influence of a non-resonant intense laser field on the optical absorption and Raman scattering processes in ZnO/Mg0.2Zn0.8O quantum wells is theoretically investigated. It is shown that the dressing field significantly modifies the confinement potential and reshapes the electronic wave functions, leading to tunable shifts in intersubband transition energies and changes in the dipole matrix elements. These laser-induced effects produce notable variations in the absorption spectrum and strongly modulate the Raman differential cross section and Raman gain. Under the application of the non-resonant laser field, the Raman gain is enhanced by almost a factor of four, whereas off-resonant pumping results in much weaker but still field-dependent responses. The results demonstrate that intense laser fields provide an effective tool to dynamically control the optical and Raman properties of ZnO-based quantum well structures.

Abstract: Nanoscale conductors and interfaces exhibit anomalous AC transport and enhanced superconducting critical temperatures that extend beyond conventional electron-phonon descriptions. We propose a complementary mechanism arising from the inertial response of a $\mathbb{Z}_3$-graded vacuum sector to time-varying electromagnetic fields. In-medium renormalization softens TeV-scale vacuum modes into low-energy collective excitations at surfaces and interfaces, introducing a characteristic response time $\tau_{\rm vac}$. This vacuum inertia modifies the effective conductivity, leading to frequency-dependent features such as high-frequency skin depth saturation, non-monotonic surface resistance, and enhanced macroscopic quantum coherence in nanostructures. Quantitative, ab initio predictions for skin depth plateaus, loss spectrum characteristics, and critical dimension effects on nanowire $T_c$ are derived and found to be consistent with experimental observations in high-purity metals and interface superconductors. The framework provides a unified perspective on these mesoscopic anomalies, bridging algebraic high-energy structures with low-energy quantum materials phenomena.

Abstract: We present a theoretical calculation of optical functions for CdSe Nanoplatelets with excitons, in an external homogeneous electric field of an arbitrary strength. We consider various configurations, with the external field parallel and perpendicular to the platelet growth axis. With the help of the real density matrix approach, we calculate the linear electro-optical functions of CdSe nanoplatelets, taking into account the effect of a dielectric confinement on excitonic states. The impact of platelet geometry (thickness, lateral dimension), and on the applied field strength, on the spectrum, is discussed.

Abstract: Non-equilibrium materials often exhibit a complex interplay between reversible elastic responses and irreversible processes such as viscous dissipation, structural relaxation, and aging. Classical constitutive models typically describe these behaviors using a single temporal variable, which can obscure the distinct physical mechanisms involved and require empirical memory kernels to account for history dependence. In this work, we address this limitation by introducing a temporal duality framework in which material behavior is governed by two coupled time regimes: a reversible time coordinate associated with elastic, time-symmetric dynamics, and an irreversible time coordinate associated with dissipative, aging, and time-asymmetric evolution. This dual-time formulation enables a unified description of viscoelasticity, memory effects, and aging, while providing structural clarity to the thermodynamic origins of irreversibility. Classical models are recovered as limiting cases, and illustrative examples show how the framework can reproduce stress–relaxation and aging behaviors commonly observed in polymers and disordered materials. This approach offers a new pathway for interpreting and modeling time-dependent behavior in non-equilibrium systems without relying on phenomenological assumptions.

Abstract: Standard \( \Lambda \)CDM cosmology successfully parameterizes the universe but lacks a first-principles derivation for its energy density components (\( \Omega_c, \Omega_b, \Omega_\Lambda \)). Following recent work on arithmetic interferometry and topological phase structures, we propose the hypothesis of \( \textit{Universal Topological Convergence} \). We postulate that the modular properties of the finite field \( \mathbb{Z}_{30} \) govern stability across scales from quantum to cosmological. We derive a modified Einstein-Hilbert action where the cosmic energy budget is partitioned by algebraic topology: Dark Matter corresponds to the stable coprime generators (\( \phi(30)/30 \approx 26.67\% \)), Baryonic Matter to the surface gauge coupling (\( 2\pi\alpha_{\text{eff}} \approx 4.9\% \)), and Dark Energy to the modular residue (\( \approx 68.43\% \)). We validate this model against Planck 2018 data (agreement \( <0.4\sigma \) across all components) and perform a rigorous \( \chi^2 \) analysis using the Pantheon Sample of 1048 Type Ia Supernovae. The topological model achieves a superior fit (\( \chi^2_{\text{Z30}} = 1040.49 \) vs \( \chi^2_{\Lambda\text{CDM}} = 1041.36 \)) while using fewer free parameters, yielding a decisively better Bayesian Information Criterion (\( \Delta\text{BIC} = -7.87 \)). This suggests that the universe operates as a base-30 modular system where the cosmic composition emerges from string-theoretic number theory rather than environmental fine-tuning.

Abstract: Defect-based quantum emitters in gallium nitride (GaN) have recently emerged as highly promising quantum light sources for quantum information technologies. Dephasing processes lead to the broadening of the photoluminescence (PL) linewidth, thereby limiting photon indistinguishability. Experimental studies of GaN defect emitters integrated with solid immersion lenses have revealed a clear temperature dependence of both the PL linewidth and lineshape. In this paper, we present a rigorously derived theoretical model that explains the temperature-dependent evolution of the PL linewidth and lineshape. This theoretical framework is not only applicable to GaN, but is also instructive for defect emitters in other wide-bandgap solid-state materials.

Abstract: We develop a symmetry-based reconstruction of the vacuum impedance and the fine-structure constant. Hyperbolic geometry and discrete sectorization of the electromagnetic field plane are the only input assumptions. The construction identifies a unique integer-square hyperbolic selector that fixes the electric–magnetic partition without adjustable parameters. This yield the geometric part of the vacuum impedance when combined with the quantum scale $h/e^{2}$. The same discrete structure provides a normalization for the fine-structure constant through a universal sector angle $\pi/24$, connecting topological quantization phenomena in metals and alloys, including Berry phases, Zak phases, and quantized Hall responses. The resulting framework places electromagnetic constants within a unified geometric–topological setting and suggests experimentally accessible consequences in systems with discrete rotational or modular symmetry.

Abstract: Fermi arcs appear as the surface states at the boundary of a three-dimensional topological semimetal with the vacuum, reflecting the Chern number (C) of a nodal point in the momentum space, which represents singularities (in the form of monopoles) of the Berry curvature. They are finite arcs, attaching/reattaching with the bulk-energy states at the tangents of the projections of the Fermi surfaces of the bands meeting at the nodes. The number of Fermi arcs grazing onto the tangents of the outermost projection equals C, revealing the intrinsic topology of the underlying bandstructure, which can be visualised in experiments like ARPES. Here we outline a generic procedure to compute these states for generic nodal points, (1) whose degeneracy might be twofold or multifold; and (2) the associated bands might exhibit isotropic or anisotropic, linear- or nonlinear-in-momentum dispersion. This also allows us to determine whether we should get any Fermi arcs at all for C = 0, when the nodes host ideal dipoles.

Abstract: Externally applied electric fields are widely employed during thin-film deposition to im-prove film uniformity, texture and densification. Despite extensive experimental evidence, the physical mechanisms by which such fields influence nucleation, surface diffusion, is-land coalescence and interface stability remain theoretically fragmented. Classical thin-film growth models assume a field-free energetic landscape and therefore provide limited predictive guidance for field-assisted manufacturing strategies. In this work, we introduce the Field-Driven Growth Model (FDGM), a unified theoretical framework that incorporates field–matter interactions directly into the free-energy func-tional governing thin-film growth. By explicitly accounting for effective dipolar coupling arising from field-induced polarization of surface species, predominantly quadratic in the field amplitude and consistent with linear-response polarization, the model consistently modifies the fundamental processes of nucleation, surface diffusion and coalescence. At the continuum scale, the FDGM predicts a field-induced stabilization mechanism that suppresses long-wavelength roughening modes and defines a field-controlled morpho-logical crossover wavelength (field-controlled cutoff). The FDGM demonstrates that field-assisted nucleation bias, anisotropic surface diffusion, field-biased coalescence pathways and morphological stabilization are not independent phenomena, but multiscale manifestations of a single energy-minimization principle act-ing on a field-modified energy landscape. By providing analytical stability criteria and explicit links between external field parameters and morphological outcomes, the model establishes a predictive foundation for the manufacturing of thin films with improved uniformity in advanced thin-film-based devices. The framework is broadly applicable to deposition techniques such as sputtering, pulsed-laser deposition, chemical vapor depo-sition and atomic layer deposition.

Abstract: This paper investigates percolation transitions in a disordered L-C system composed of inductors and capacitors (non-dissipative reactive elements). These transitions occur between different percolating states, resulting in distinct, constant values of the effective conductivity. We employ an exact approach based on the rotational symmetry of two-dimensional DC equations. A new type of phase transition is identified for these non-dissipative systems by analogy to a topological transition. The characteristics of these transitions, which are analogs of topological invariants, are calculated. We propose that these transitions may be considered a classical analog to quantum transitions, such as the quantum Hall effect.

Abstract: Based on the derived equation of state for crystals under external stress and temperature, we derived that for non-crystal systems under general external stress and temperature and discussed its relationship with the Macroscopic Mechanical Equilibrium Condition.

Abstract: The conventional framework for quantum statistics is built upon gauge theory, where particle exchanges generate path-dependent phases. However, the apparent consistency of this approach masks a deeper question: is gauge invariance truly sufficient to satisfy the physical requirement of indistinguishability? We demonstrate that gauge transformations, while preserving probabilities in a formal sense, are inadequate to capture the full constraints of identical particles, thereby allowing for unphysical statistical outcomes. This critical limitation necessitates a reconstruction of the theory by strictly enforcing indistinguishability as the foundational principle, thus moving beyond the conventional topological paradigm. This shift yields a radically simplified framework in which the statistical phase emerges as a path-independent quantity, \( \alpha = e^{\pm i\theta} \), unifying bosons, fermions, and anyons within a single consistent description. Building upon the operator-based formalism of Series I and the dual-phase theory of Series II, we further present an exact and computationally tractable approach for solving N-anyon systems.

Abstract: The 2-D Ti3C2 (MXene) materials have found applications in various fields, partic-ularly as a candidate for field emission electron source when mixed with carbon nano-tubes (CNTs) as the electron source material. In this study, a novel multilayer film structure utilizing Ti₃C₂ (MXene) / CNTs and fabricate a unique field emitter device using these 2-D Ti3C2 (MXene) / CNT materials have been presented. The material ex-hibits a tensile stress of 950 MPa and a low elongation at break of 8%. Specifically, uti-lizing the sharp edges of this material for emission, the field emission characteristics of Ti3C2 (MXene) and Ti3C2 (MXene) / CNT have been compared. The field emission char-acteristics of Ti3C2 (MXene) and Ti3C2 (MXene) / CNT have been compared. Measuring the current density is up to 3.49 A∙cm-2 at an electric field of 2.91 V∙µm−1, It has low turn-on field (Eon) 1.6 V∙ m-1, and low threshold electric field (Eth) 0.22 μA.cm-2. The field enhancement factor β of Ti3C2 (MXene) / CNT is about 4.5 times more than pristine Ti3C2 (MXene). Utilizing curved tip of Ti3C2 (MXene) / CNT emission, the field emission current device slightly increases surround the vacuum degree from 1.010-3 Pa to 4.710-5, and the current can be emitted steadily for a duration of 1 hour under the voltage of 723 V and vacuum level of 1.010-3 Pa. Those results provide that this kind of multilayer film Ti₃C₂ (MXene) / CNT exhibits exceptional mechanical properties and can be easily shaped, particularly suit to fabricate vacuum electronic devices and other uses.

Abstract: A model of nanoparticles has been designed to resemble partly self-similar ferroelastic star-like domain textures. Numerical computations have been used to find the equilibrium configurations of magnetisation in such systems. As expected from symmetry, the self-similar initial states give room to other types of domain structure as a function of the star parameters. When relaxed without external field the self-similar pattern mostly turns to a massive vortex in the center with radially oriented domains in the peripheral arms of the star. In contrast to that a random initial state ends up in a configuration of a triple valve with one input and two outputs or vice versa in analogy to logical gates. A treatment with an in-plane magnetic field always leads to the valve configuration. The triple-valve states turn out stable and the vortex ones metastable. The results may be useful in the design of magnetic based logic devices.

Abstract: The main aim in this paper is to present a simplified (temperature-dependent) version of the quantum statistical model for computing the equation of state of electrons in materials. For this purpose, the Englert-Schwinger approximation scheme within the quantum statistical model is extended to finite temperatures. This procedure leads to a modified Thomas-Fermi-Dirac model. Schwinger and co-workers had originally demonstrated this procedure for the case of zero-temperature, and applied it to compute the electronic properties of cold free atoms. In this paper, a new algorithm is developed to solve the modified Thomas-Fermi-Dirac model, and the numerical results obtained for Cu and Al are compared with those of the exact quantum statistical model. Good agreement is found particularly for thermal component of electron equation of state. The present approach, at much less efforts, would be useful in high-energy-density physics as thermal component of electron properties alone are needed in equation of state theory. Derivation of explicit expressions of different contributions (viz. kinetic, gradient, exchange and exchange-correlation terms) to the free energy functional, its stationary property, finite-temperature corrections to energy of strongly bound electrons, and (iv) details of the new algorithm are provided in the Appendix.

Abstract: A brief review of orientational phase transitions and thermodynamic properties of various magnets. These methodological guidelines are intended for students studying the section "Theory of Phase Transitions" in the course "Theory of Solids", as well as the section "Magnetic Phase Transitions" in the course "Theory of Magnetism". They can be used in preparation for laboratory and seminar classes in these courses, and for independent research work by students of the Faculty of Physics.

Abstract: We investigate the role of single-ion anisotropy in stabilizing higher-order skyrmion crystal phases in centrosymmetric magnets under D3d symmetry. Using a classical spin model that incorporates both single-ion and D3d-type magnetic anisotropies, we perform simulated annealing calculations to explore the ground-state spin configurations. We find that a skyrmion crystal with a skyrmion number of two is stabilized over a wide range of parameters of single-ion anisotropy and D3d-type anisotropy. We also show that the skyrmion core position shifts from an interstitial site to an on-site location as the magnitude of the easy-axis single-ion anisotropy increases. Furthermore, we demonstrate that the magnetic field drives a variety of topological phase transitions depending on the sign and magnitude of the single-ion and D3d-type anisotropies. These results provide a possible microscopic understanding of how complex topological spin textures can be stabilized in centrosymmetric D3d magnets, suggesting that multiple phases with topological spin textures could emerge even in the absence of the Dzyaloshinskii–Moriya interaction.

Abstract: . This work studies relaxation processes and transient currents in a disordered multi-component LC system, consisting of inductive and capacitive reactances (non-dissipative elements). At first glance, relaxation processes seem impossible in non-dissipative systems such as LC systems. Nevertheless, at the percolation threshold, we obtain the exact solution for the multi-component system, consisting of two different types of inductors and two different capacitors with random displacement and connections. It was shown that the effective conductivity of such a non-dissipative disordered system has a real value. This means that relaxation and transient currents arise in this problem. The relaxation times for these processes are established for both low and high frequencies. A physical interpretation of the obtained results is given.

Abstract: The development of economical and scalable methods for synthesizing high-quality graphene remains a pivotal challenge in materials science. This study presents an efficient approach for synthesizing turbostratic graphene with micron-sized domains from an accessible bioprecursor – activated charcoal – using fast Joule heating. We demonstrate that ultra-rapid thermal annealing (~16.2 kJ/g, up to 3000 K) triggers a phase transition from amorphous carbon to a highly graphitized structure. Comprehensive characterization via SEM, AFM, Raman spectroscopy, and XRD revealed the formation of large flakes with lateral dimensions up to 1.5 µm and thicknesses ranging from 4 to 200 nm. Raman mapping further uncovered a heterogeneous structure with alternating regions exhibiting different degrees of interlayer coupling, characteristic of turbostratic stacking. The key feature of the material is its turbostratic layer stacking, confirmed by the combination of XRD data showing an interlayer distance of 3.436 Å and Raman spectra characteristic of decoupled graphene layers. The synthesized material exhibits excellent electrical transport properties, with a bulk resistivity of 0.51 Ω·cm – an order of magnitude lower than that of the initial charcoal. These findings highlight the potential of the developed method for producing electrode materials for energy storage devices and conductive composites.

Abstract: Fermion bound states in the core of a line-shaped vortex of a two-dimensional topological superconductor are investigated. The superconducting pairing potential, described in terms of elliptical coordinates, vanishes along a line defect with the two foci at the endpoints. The superconductivity is induced into a topological insulator via proximity effect with a type II s-wave superconductor. The spin and the momentum are perpendicularly locked by the strong spin-orbit coupling via Rashba interaction. A zero-energy Majorana state arises from the Berry phase together with a sequence of equally spaced fermion excitations. By solving the Bogoliubov-de Gennes equations using the method employed by Caroli, de Gennes and Matricon we calculate the energies, the wavefunctions and spin-polarization of the bound states. An analytic expression for the local density of states within the vortex is obtained.