Submitted:
31 July 2025
Posted:
01 August 2025
Read the latest preprint version here
Abstract
Keywords:
1. Introduction
1.1. The Missing Transport Field: Spacetime Diffusivity
1.2. Quantum Measurement Incompatibility in Cosmological Observations
1.3. Foundational Postulates and Scale Unification
- Postulate 1 (Invariant Time-like Information):
- Causal structure enforces information propagation at the fundamental rate:
- Postulate 2 (Diffused Spacetime):
- A spacetime diffusivity field with dimensions evolves according to:
2. Theoretical Framework
2.1. Spacetime Framework and Information Transport
2.1.1. Time-like Structure from Causal Constraints
Invariant foliation time.
Claim.
2.2. Physical Interpretation of Time-like Layers and Emergent Dynamics
2.2.1. Mathematical Formalization
- Maximal symmetry: No preferred directions, ensuring informational isotropy
- BGV consistency: Closed geometry accommodates required past boundaries
- Finite information capacity: Bounded information content per temporal slice
- Computational tractability: Well-defined boundaries for flux calculations
- Observational compatibility: Current CMB constraints permit slight positive curvature
- Wave-equation symmetry: Maxwell’s equations yield spherical solutions ensuring uniform information propagation [26]
- Huygens–Fresnel principle: Spherical wavelet reconstruction preserves isotropy [27]
2.3. Physical Rationale for the Two Postulates
Operational measurability.
2.4. Spacetime Diffusivity: The Missing Transport Field
2.4.1. Foundational Motivation for the Spacetime Diffusivity Field
2.4.2. Physical Motivation for the Spacetime Diffusivity
- Brownian (mass) diffusivity:D in Fick’s law governs the stochastic spreading of particles and chemical species.
- Thermal diffusivity: governs heat transport through matter
- Kinematic viscosity: governs momentum transport in fluids
- Spacetime diffusivity: governs information transport between temporal layers
2.4.3. Connections to Quantum Gravity
2.5. Mass-Energy and Information Flux as Conjugate Variables
2.5.1. Information Diffusivity and Localization Conjugacy
Information State Duality
- Flowing information (energia fluens): Dynamic information transport between temporal layers
- Localized information (energia locata): Crystallized, captured information such as sharp astronomical images; massive bodies
Conjugate Dynamics
2.6. The Cosmological Uncertainty Principle
2.6.1. Derivation from Primitive Postulates via an Action Principle
- P1:
- Information propagates at light speed: .
- P2:
- Spacetime diffusivity grows at that same rate: .
- P3:
- Action principle: the physical history of the field extremises a first–order action .
Action.
Classical equations of motion.
Canonical structure.
Quantisation and commutator.
Domains.
Cosmological Uncertainty Principle (CUP).
2.6.2. Mathematical Structure: Domains, Self-Adjointness, and the Hilbert Space
2.6.3. Derivation of the Uncertainty Relation
2.6.4. Physical Context-Dependent Amplification
Local Quantum Limit ():
Extended System Amplification ():
2.6.5. Alternative Derivation via Energy-Time Uncertainty
2.7. Information-Pixel Amplification: Determination of the k-Factor
2.7.1. Spacetime Pixelation and Coherence Length
Operator derivation of the amplification factor.
2.7.2. Physical Interpretation and Milky Way Application
Local vs. cosmic measurements
- Laboratory scale (): — the CUP reduces to the usual Robertson bound.
- Galactic scale (): for , giving an enormous amplification.
- Cosmological horizon (): with . (For the Planck-coherence idealisation the same formula would give .)
Milky Way dark-matter prediction
2.7.3. Connection to Established Physics
| Framework | Conjugate pair | Amplification | Uncertainty bound | Sector affected |
|---|---|---|---|---|
| Heisenberg (UP) | none | position, momentum | ||
| Kempf–Scardigli (GUP) | UV deformation | position, momentum | ||
| EUP (IR form) | IR deformation | position, momentum | ||
| CUP (this paper) | diffusivity, mass |
| Pair | Commutator | Uncertainty | Physical Context |
|---|---|---|---|
| Standard QM | |||
| (local) | Local CUP | ||
| (extended) | Astronomical CUP |
2.7.4. Relation to Prior Extended Uncertainty Principles
2.7.5. Physical Implications and Interpretational Remarks
2.7.6. Remarks on Generalizations
2.8. Information Flux and Global Structure
Operational scale unification from ITP & DTP.
Division of roles.
2.8.1. Holographic Information Bounds
3. Results
3.1. Quantum-Gravitational Scale Unification
3.1.1. Fundamental Time Scales from Diffusion Parameter
3.1.2. Light-cone Foundation
3.1.3. Physical Significance
- Scale bridging: Quantum gravity ( s) and cosmic evolution ( s) emerge from identical information-theoretic principles
- Causal foundation: Both scales arise from the same underlying causal structure encoded in light cone geometry
- Static universe consistency: The above derivations came from the idea that time-indices are fixed features of the foliation manifold (see Subsection 2.1).
3.2. A Cosmological Horizon Temperature
3.2.1. Horizon-Scale Temperature and Coherence Derivation
3.3. Observational Predictions: Milky Way Toy Model
3.3.1. FRB-Motivated Diffusivity
3.3.2. Coherence Length
3.3.3. Milky Way Prediction
Null-Violation Test (Milky Way Scale)
- Note: This bound scales with distance D; larger systems impose stricter constraints.
Remark: Mass Uncertainty as Planckian Pixel Noises
The Coherence Length as Ultimate Theoretical Target
3.4. Observational Predictions: Local Group Toy Models
3.4.1. Andromeda (M31)
FRB-Motivated Diffusivity
Distance and Observed Uncertainty
3.4.2. Triangulum (M33)
FRB-Motivated Diffusivity
Distance and Observed Uncertainty
3.4.3. Required Coherence Lengths
Andromeda (M31)
Triangulum (M33)
3.4.4. Quantity Check
M31 Verification
M33 Verification
3.4.5. Theoretical Significance
Universal Quantum Framework
Coherence Scale Discovery
Exact Quantitative Agreement
Predictive Challenge
3.4.6. Dark Matter Reinterpretation
3.5. Information Capacity Hierarchy
3.6. Connections to Gravitational Phenomena
3.7. Summary of Key Results
- Scale Unification: Both Planck time and Hubble time emerge from a single diffusion parameter, spanning 60 orders of magnitude
- Cosmological Horizon Temperature: Fundamental thermal limit K at the cosmic boundary, exceeding the classical Gibbons-Hawking temperature by factor
- Testable Predictions: Specific constraints on astronomical measurements through precision-uncertainty trade-offs, offering pathways for empirical validation
- Information Hierarchy: Deep structure spanning from bits (Planck) to bits (cosmic), revealing the informational organization of spacetime
4. Discussion
4.1. Scale Unification as Evidence for Fundamental Reality
4.1.1. Unified Origin of Planck and Hubble Times via Information Diffusivity
In summary, the emergence of Planck and Hubble times from a single information diffusivity parameter ϵ is a reflection of the fact that the universe’s smallest and largest observable scales are governed by the same principle: the irreducible limits on information propagation set by quantum gravity, relativity, and cosmic expansion.
4.2. Resolution of the Problem of Time
4.2.1. Scale-Invariant Information Constraints
- Conclusion. Time exhibits a uniform operational character from Planckian to cosmological regimes: it is the observers’ experience resulting from interaction with a finite information manifold subject to light-speed mediation. Ontologically, under exact General Relativity, the universe constitutes an eternal block spacetime; phenomenologically, temporality emerges from scale-invariant constraints on accessible information. □
4.2.2. Present State Inaccessibility and Gravitational Emergence
Gravitational Emergence Through Information-Mass Conjugacy
Cosmic Observational Consequences
Unified Framework
- Local scale: CUP optimization drives gravitational clustering through spatial concentration of energia locata
- Temporal experience: Present state inaccessibility creates apparent cosmic evolution through finite information propagation
- Cosmic scale: CUP constraints govern observational precision trade-offs in astronomical measurements
4.3. Quantum Gravity and Information Theory Connections
4.4. Quantum-Informational Foundations of Cosmic Structure
4.4.1. Information-Theoretic Bounds
4.4.2. Measurement Trade-offs and Dark Matter
4.5. Implications for Observational Cosmology
- FRB Measurement Trade-offs: Timing-optimized and mass-optimized analysis pipelines should yield systematically different precision trade-offs for identical FRB sources
- CMB Parameter Correlations: Further precision improvements may reveal systematic uncertainties in mass-related parameters that reflect fundamental rather than instrumental limitations
- Survey Method Dependencies: Systematic differences between spectroscopic and lensing dark matter estimates should persist even with improved methodologies
- Redshift-Distance Scaling: Dark matter uncertainty should exhibit specific scaling with cosmological distance independent of source luminosity or morphology
4.6. CUP versus de Sitter Horizon Temperatures
5. Conclusion
5.1. Principal Discoveries
5.2. Theoretical Significance and Observational Predictions
5.3. Future Directions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
A. Gedankenexperiment: The Dispersion–Mass Limit
A.1. Experimental Setup
- FRB Dispersion Properties. Using radio telescopes, she quantifies dispersion measures and pulse broadening—collectively the “spacetime diffusivity” .
- Host Galaxy Mass. Gravitational lensing and velocity dispersions yield the total mass m of each FRB host system.
A.2. The Distance-Dependent Puzzling Pattern
A.3. Information-Pixel Discovery
A.3.1. Trial-and-error calibration of .
| Trial | [kg] | Assessment | |
|---|---|---|---|
| 1 | 50 | (high) | |
| 2 | 100 | (high) | |
| 3 | 150 | (low) | |
| Refine: | |||
| 4 | 120 | (close) | |
| 5 | 130 | (close) | |
| Final range: | |||
| 6 | 125 | ||
| 7 | 126 | (optimal) | |
| 8 | 127 | (low) | |
A.4. Information-Resource Competition
A.5. Physical Implications
B. List of Symbols
| Symbol | Meaning |
|---|---|
| m | Rest mass (energia locata) |
| Spacetime diffusivity (energia fluens) | |
| D | Path length of observation |
| Quantum-information coherence length | |
| k | Amplification factor |
| Z | Planck–Hubble area-diffusion parameter |
C. Functional–Analytic Foundations of the CUP
C.1. Hilbert Space and Basic Operators
C.2. Symmetry and Essential Self-Adjointness
C.3. Canonical Commutation Relation and CUP
C.4. Uniqueness of the Representation
D. Operator Domains and Mass Positivity
Mass positivity.
- Option A (recommended): full-line representation. Retain and interpret m as a signed conjugate quantity whose sign labels the orientation of the -flux. All measurable temperatures and capacities in the present framework depend on , and the sign is unobservable in the predictions we make. This option avoids boundary subtleties and preserves the canonical commutator (D.1) on the standard self-adjoint domains.
- Option B: enforcing . Demanding a positive spectrum for the mass operator corresponds to restricting to the half-line. The standard momentum operator defined on with local boundary conditions is not self-adjoint; there is no self-adjoint extension that acts as and keeps the boundary at impenetrable. Consequently, one must either (i) use a positive operator such as (with spectrum ) at the price of modified uncertainty relations, or (ii) adopt a self-adjoint “reflecting momentum”/POVM description tailored to a half-line, or (iii) move to an affine pair with , which guarantees and yields .
Domains.
E. Reduction of the Cosmological Uncertainty Principle to the Heisenberg Limit ()
E.1. Purpose
E.2. Starting assumptions
E.3. Rescaling to position–momentum variables
- Commutator
E.4. Robertson–Schrödinger inequality
- Returning to
E.5. Interpretation
- is the generator of translations in spacetime–information diffusivity , just as generates translations in .
- When (i.e. ) the CUP does not strengthen Heisenberg’s principle; it is Heisenberg’s principle in rescaled variables.
- For extended baselines , the amplification factor enters multiplicatively, giving the cosmological enhancement discussed in the main manuscript.
E.6. Addendum: Dimensional Analogy Between CUP and Heisenberg Uncertainty
CUP Variables
- Diffusivity has dimensions:where x is position and v is velocity. Hence, diffusivity resembles a product of velocity and position.
- Massm enters classical momentum as:
Conjugate Mirrors
Conclusion
E.7. Identifying the Analogy with Position–Momentum Uncertainty
| Heisenberg QM | Local CUP () | Interpretation |
|---|---|---|
| Position ∼ diffusivity rescaled by c | ||
| Momentum ∼ inertial mass scaled by c | ||
| Canonical conjugates | ||
| Identical structure |
References
- Friedmann, A. Über die Krümmung des Raumes. Zeitschrift für Physik 1922, 10, 377–386. [Google Scholar] [CrossRef]
- Lemaître, G. Un univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extra-galactiques. Annales de la Société Scientifique de Bruxelles 1927, 47, 49–59. [Google Scholar]
- Weinberg, S. Cosmology; Oxford University Press: Oxford, 2008. [Google Scholar]
- Planck Collaboration. Planck 2018 results. VI. Cosmological parameters. Astronomy & Astrophysics 2020, 641, A6. [Google Scholar]
- Page, D.N.; Wootters, W.K. Evolution without evolution: Dynamics described by stationary observables. Physical Review D 1983, 27, 2885–2892. [Google Scholar] [CrossRef]
- Wheeler, J.A. Superspace and the nature of quantum geometrodynamics. Annals of Physics 1967, 2, 604–614. [Google Scholar] [CrossRef]
- DeWitt, B.S. Quantum theory of gravity. I. The canonical theory. Physical Review 1967, 160, 1113–1148. [Google Scholar] [CrossRef]
- Einstein, A. Die Feldgleichungen der Gravitation. Sitzungsberichte der Königlich Preußischen Akademie der Wissenschaften 1915, pp. 844–847.
- Penrose, R. The road to reality: A complete guide to the laws of the universe; Jonathan Cape: London, 2004. [Google Scholar]
- Minkowski, H. Raum und Zeit. Physikalische Zeitschrift 1908, 10, 75–88. [Google Scholar]
- Einstein, A. On the movement of small particles suspended in stationary liquids required by the molecular-kinetic theory of heat. Annalen der Physik 1905, 17, 549–560, Translated from German original. [Google Scholar] [CrossRef]
- Wilde, M.M. Quantum Information Theory, 2nd ed.; Cambridge University Press, 2017.
- Zurek, W.H. Decoherence, einselection, and the quantum origins of the classical. Reviews of Modern Physics 2003, 75, 715–775. [Google Scholar] [CrossRef]
- Lieb, E.H.; Robinson, D.W. The finite group velocity of quantum spin systems. Commun. Math. Phys. 1972, 28, 251–257. [Google Scholar] [CrossRef]
- Susskind, L. Computational complexity and black hole horizons. Fortschritte der Physik 2016, 64, 24–43. [Google Scholar] [CrossRef]
- ’t Hooft, G. Dimensional Reduction in Quantum Gravity. arXiv preprint 1993, [gr-qc/9310026]. Presented at the Salamfest, Trieste, 1993.
- Susskind, L. The World as a Hologram. Journal of Mathematical Physics 1995, 36, 6377–6396. [Google Scholar] [CrossRef]
- Bekenstein, J.D. Black holes and entropy. Physical Review D 1973, 7, 2333–2346. [Google Scholar] [CrossRef]
- Landauer, R. Irreversibility and heat generation in the computing process. IBM J. Res. Dev. 1961, 5, 183–191. [Google Scholar] [CrossRef]
- Joos, E.; Zeh, H.D. The emergence of classical properties through interaction with the environment. Z. Phys. B 1985, 59, 223–243. [Google Scholar] [CrossRef]
- Penrose, R. Shadows of the Mind: A Search for the Missing Science of Consciousness; Oxford University Press: Oxford, 1996. [Google Scholar]
- Borde, A.; Guth, A.H.; Vilenkin, A. Inflationary spacetimes are incomplete in past directions. Physical Review Letters 2003, 90, 151301. [Google Scholar] [CrossRef] [PubMed]
- Wald, R.M. General Relativity; University of Chicago Press: Chicago, 1984. [Google Scholar]
- Hawking, S.W.; Ellis, G.F.R. The Large Scale Structure of Space–Time; Cambridge University Press, 1973. [CrossRef]
- Misner, C.W.; Thorne, K.S.; Wheeler, J.A. Gravitation; W. H. Freeman: San Francisco, 1973. [Google Scholar]
- Jackson, J.D. Classical Electrodynamics, 3rd ed.; John Wiley & Sons: New York, 1998. [Google Scholar]
- Born, M.; Wolf, E. Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, 7th (expanded) ed.; Cambridge University Press: Cambridge, 1999.
- Caianiello, E.R. Is There a Maximal Acceleration? Lettere al Nuovo Cimento 1981, 32, 65–70. [Google Scholar] [CrossRef]
- Kovtun, P.; Son, D.T.; Starinets, A.O. Viscosity in Strongly Interacting Quantum Field Theories from Black Hole Physics. Physical Review Letters 2005, 94, 111601. [Google Scholar] [CrossRef]
- Nelson, E. Derivation of the Schrödinger Equation from Newtonian Mechanics. Physical Review 1966, 150, 1079–1085. [Google Scholar] [CrossRef]
- Lloyd, S. Ultimate physical limits to computation. Nature 2000, 406, 1047–1054. [Google Scholar] [CrossRef]
- Hawking, S.W. Particle Creation by Black Holes. Communications in Mathematical Physics 1975, 43, 199–220. [Google Scholar] [CrossRef]
- Jacobson, T. Thermodynamics of spacetime: The Einstein equation of state. Physical Review Letters 1995, 75, 1260–1263. [Google Scholar] [CrossRef]
- Verlinde, E.P. On the origin of gravity and the laws of Newton. Journal of High Energy Physics 2011, 2011, 029. [Google Scholar] [CrossRef]
- Sakurai, J.J.; Napolitano, J. Modern Quantum Mechanics, 3rd ed.; Cambridge University Press: Cambridge, 2017. [Google Scholar]
- Robertson, H.P. The uncertainty principle. Physical Review 1929, 34, 163–164. [Google Scholar] [CrossRef]
- Heisenberg, W. Über den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik. Zeitschrift für Physik 1927, 43, 172–198. [Google Scholar] [CrossRef]
- Mandelstam, L.; Tamm, I. The uncertainty relation between energy and time in non-relativistic quantum mechanics. Journal of Physics USSR 1945, 9, 249–254. [Google Scholar]
- Messiah, A. Quantum Mechanics; Dover Publications: New York, 1999. [Google Scholar]
- Tiesinga, E.; Mohr, P.J.; Newell, D.B.; Taylor, B.N. CODATA recommended values of the fundamental physical constants: 2018. Rev. Mod. Phys. 2019, 91, 015006. [Google Scholar] [CrossRef]
- Preskill, J. Quantum Computing in the NISQ era and beyond. Quantum 2018, 2, 79. [Google Scholar] [CrossRef]
- Steane, A.M. Error correcting codes in quantum theory. Phys. Rev. Lett. 1996, 77, 793–797. [Google Scholar] [CrossRef] [PubMed]
- Anastopoulos, C.; Hu, B.L. Probing a gravitational cat state. Class. Quantum Grav. 2013, 30, 165007. [Google Scholar] [CrossRef]
- Bretherton, C.S.; Widmann, M.; Dymnikov, V.P.; Wallace, J.M.; Bladé, I. The Effective Number of Spatial Degrees of Freedom of a Time-Varying Field. Journal of Climate 1999, 12, 1990–2009. [Google Scholar] [CrossRef]
- Wang, X.; Shen, S.S.P. Estimation of Spatial Degrees of Freedom of a Climate Field. Journal of Climate 1999, 12, 1280–1291. [Google Scholar] [CrossRef]
- Kunz, T.; Laepple, T. Effective Spatial Degrees of Freedom of Natural Temperature Variability as a Function of Frequency. Journal of Climate 2024, 37, 2505–2529. [Google Scholar] [CrossRef]
- Cressie, N.A.C. Statistics for Spatial Data, revised ed.; Wiley: New York, 1993. [Google Scholar] [CrossRef]
- Vallejos, R.; Osorio, F. Effective sample size of spatial process models. Spatial Statistics 2014, 9, 66–92. [Google Scholar] [CrossRef]
- Griffith, D.A. Negative Spatial Autocorrelation: One of the Most Neglected Concepts in Spatial Statistics. Stats 2019, 2, 388–415. [Google Scholar] [CrossRef]
- Tennekes, H.; Lumley, J.L. A First Course in Turbulence; MIT Press: Cambridge, MA, 1972. [Google Scholar]
- Rickett, B.J. Radio Propagation Through the Turbulent Interstellar Plasma. Annual Review of Astronomy and Astrophysics 1990, 28, 561–605. [Google Scholar] [CrossRef]
- Armstrong, J.W.; Rickett, B.J.; Spangler, S.R. Electron Density Power Spectrum in the Local Interstellar Medium. The Astrophysical Journal 1995, 443, 209–221. [Google Scholar] [CrossRef]
- Susskind, L. Addendum to Computational Complexity and Black Hole Horizons. Fortschritte der Physik 2016, 64, 44–48, [arXiv:1403.5695]. [CrossRef]
- Diósi, L. A universal master equation for the gravitational violation of quantum mechanics. Phys. Lett. A 1987, 120, 377–381. [Google Scholar] [CrossRef]
- Gambini, R.; Porto, R.A.; Pullin, J.; Torterolo, S. Conditional probabilities with Dirac observables and the problem of time in quantum gravity. Phys. Rev. D 2013, 88, 063501. [Google Scholar] [CrossRef]
- Kempf, A. Uncertainty Relation in Quantum Mechanics with Quantum Group Symmetry. Journal of Mathematical Physics 1994, 35, 4483–4496. [Google Scholar] [CrossRef]
- Scardigli, F. Generalized Uncertainty Principle in Quantum Gravity from Micro-Black Hole Gedanken Experiment. Physics Letters B 1999, 452, 39–44. [Google Scholar] [CrossRef]
- Hossenfelder, S. Minimal Length Scale Scenarios for Quantum Gravity. Living Reviews in Relativity 2013, 16. [Google Scholar] [CrossRef]
- Gibbons, G.W.; Hawking, S.W. Cosmological event horizons, thermodynamics, and particle creation. Physical Review D 1977, 15, 2738–2751. [Google Scholar] [CrossRef]
- Ho, J.; Jain, A.; Abbeel, P. Denoising Diffusion Probabilistic Models. Advances in Neural Information Processing Systems 2020, 33, 6840–6851, [2006.11239]. [Google Scholar]
- McConnachie, A.W. Distances and Metallicities for 17 Local Group Galaxies. Mon. Not. R. Astron. Soc. 2005, 356, 979–997. [Google Scholar] [CrossRef]
- Corbelli, E.; Salucci, P. The extended rotation curve and the dark matter halo of M33. Mon. Not. R. Astron. Soc. 2003, 342, 199–207. [Google Scholar] [CrossRef]
- Smoot, G.F.; et al. Structure in the COBE differential microwave radiometer first-year maps. The Astrophysical Journal 1992, 396, L1–L5. [Google Scholar] [CrossRef]
- Hinshaw, G.; et al. Nine-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: cosmological parameter results. The Astrophysical Journal Supplement Series 2013, 208, 19. [Google Scholar] [CrossRef]
- Bousso, R. The holographic principle. Reviews of Modern Physics 2002, 74, 825–874. [Google Scholar] [CrossRef]
- Perivolaropoulos, L. Cosmological horizons, uncertainty principle, and maximum length quantum mechanics. Physical Review D 2017, 95, 103523. [Google Scholar] [CrossRef]
- Ali, A.F.; Inan, E. Cosmological uncertainty principle and dark energy. Classical and Quantum Gravity 2025, 42, 025003. [Google Scholar]
- Volovik, G.E. On the Global Temperature of the Schwarzschild–de Sitter Spacetime. JETP Letters 2023, 118, 8–13. [Google Scholar] [CrossRef]
- Volovik, G.E. First law of de Sitter thermodynamics. arXiv e-prints 2025, p. arXiv:2504.05763, [arXiv:gr-qc/2504.05763]. Proposes a local de Sitter temperature T=H/π.
- Bonneau, G.; Faraut, J.; Valent, G. Self-adjoint extensions of operators and the teaching of quantum mechanics. American Journal of Physics 2001, 69, 322–331. [Google Scholar] [CrossRef]
- Al-Hashimi, M.H.; Wiese, U.J. Canonical quantization on the half-line and in an interval based upon a new concept for the momentum in a space with boundaries. Physical Review Research 2021, 3, 033079. [Google Scholar] [CrossRef]
- Shikano, Y.; Hosoya, A. Optimal covariant measurement of momentum on a half line in quantum mechanics. Journal of Mathematical Physics 2008, 49, 052104. [Google Scholar] [CrossRef]

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |
© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).