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PhilSci-Archive: No conditions. Results ordered -Date Deposited.
Sat Apr 01 2023 00:29:17 (9 hours)
# 1.
Stern, Julio Michael (2017) Continuous versions of Haack’s puzzles: equilibria, eigen-states and ontologies. [Preprint]
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Sat Apr 01 2023 00:28:09 (9 hours)
# 2.
Shanahan, Daniel (2023) Protogravity: a quantum-theoretic precursor to gravity. Spacetime Conference 2022. pp. 153-181.
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Takamasa Kanai, Kimihiro Nomura, Daisuke Yoshida
Fri Mar 31 2023 18:53:05 (14 hours)
# 3.
Bousso’s entropy bound is a conjecture that the entropy through a null hypersurface emanating from a two-dimensional surface with a nonpositive expansion is bounded by the area of that two-dimensional surface. We investigate the validity of Bousso’s entropy bound in the spatially flat, homogeneous, and isotropic universe with an adiabatic entropy current. We find that the bound is satisfied in the entire spacetime in which a cutoff time is introduced based on the entropy density and the energy density. Compared to the previously used prescription which puts a cutoff near the curvature singularity, our criterion for introducing the cutoff is applicable even to a nonsingular universe. Our analysis provides an interpretation of the incompleteness implied by the recently proposed singularity theorem based on the entropy bounds.
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Emil J. Martinec
Fri Mar 31 2023 18:53:03 (14 hours)
# 4.
Radiation of conserved charges carried by a black hole is a rare process, whose probability is suppressed by the change in the entropy between the initial and final states. This universal result provides insight into the black hole’s internal structure and dynamics.
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Shinichi Saito
Fri Mar 31 2023 18:53:01 (14 hours)
# 5.
Stokes parameters (${\bf S}$) in Poincar\’e sphere are very useful values to describe the polarisation state of photons. However, the fundamental principle of the nature of polarisation is not completely understood, yet, because we have no concrete consensus how to describe spin of photons, quantum-mechanically. Here, we have considered a monochromatic coherent ray of photons, described by a many-body coherent state, and tried to establish a fundamental basis to describe the spin state of photons, in connection with a classical description based on Stokes parameters. We show that a spinor description of the coherent state is equivalent to Jones vector for polarisation states, and obtain the spin operators (${\bf \hat{S}}$) of all components based on rotators in a $SU(2)$ group theory. Polarisation controllers such as phase-shifters and rotators are also obtained as quantum-mechanical operators to change the phase of the wavefunction for polarisation states. We show that the Stokes parameters are quantum-mechanical average of the obtained spin operators, ${\bf S} = \langle {\bf \hat{S}} \rangle $.
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Thu Mar 30 2023 06:19:07 (2 days)
# 6.
Jacobs, Caspar (2023) Comparativist Theories or Conspiracy Theories: the No Miracles Argument Against Comparativism. [Preprint]
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Wed Mar 29 2023 05:11:38 (3 days)
# 7.
Elder, Jamee (2023) On the “Direct Detection” of Gravitational Waves. [Preprint]
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Wed Mar 29 2023 05:10:28 (3 days)
# 8.
Christian, Joy (2023) Bell’s Theorem Begs the Question. [Preprint]
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physics.hist-ph updates on arXiv.org
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Jorge E. Horvath, Rodrigo Rosas Fernandes
Tue Mar 28 2023 09:16:30 (4 days)
# 9.
Quantum Mechanics (QM) stands alone as a (very) successful physical theory, but the meaning of its variables and the status of many quantities in the mathematical formalism is obscure. This unique situation prompted the need for attribution of a physical meaning to the latter, a procedure known as interpretation. On the other hand, the study of QM is usually presented, even to future scientists, within the only framework developed by Bohr and the Copenhagen researchers, known as the Copenhagen interpretation. As a contribution to the understanding and teaching of Quantum Mechanics, aimed to a broader and deeper appreciation of its fundamentals, including contemplating alternatives and updated interpretations for physicists and philosophers interested in the study of exact sciences (through Ontology, Epistemology, Logic or the Theory of Knowledge), we present a set of Conceptual Diagrams elaborated and designed to expose and facilitate the visualization of elements intervening in any interpretation of Quantum Mechanics and apply them to several well-developed cases of the latter.
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physics.hist-ph updates on arXiv.org
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Eugene Y. S. Chua
Tue Mar 28 2023 09:16:29 (4 days)
# 10.
Taking the formal analogies between black holes and classical thermodynamics seriously seems to first require that classical thermodynamics applies to relativistic regimes. Yet, by scrutinizing how classical temperature is extended into special relativity, I argue that it falls apart. I examine four consilient procedures for establishing classical temperature – the Carnot process, the thermometer, kinetic theory, and black-body radiation. I show how their relativistic counterparts demonstrate no such consilience in defining relativistic temperature. Hence, classical temperature does not appear to survive a relativistic extension. I suggest two interpretations for this situation – eliminativism akin to simultaneity, or pluralism akin to rotation.
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physics.hist-ph updates on arXiv.org
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Eugene Y. S. Chua
Tue Mar 28 2023 09:16:28 (4 days)
# 11.
Conventional wisdom holds that the von Neumann entropy corresponds to thermodynamic entropy, but Hemmo and Shenker (2006) have recently argued against this view by attacking von Neumann (1955) and his argument. I argue that Hemmo and Shenker’s arguments fail due to several misunderstandings: about statistical-mechanical and thermodynamic domains of applicability, about the nature of mixed states, and about the role of approximations in physics. As a result, their arguments fail in all cases: in the single-particle case, the finite particles case, and the infinite particles case.
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physics.hist-ph updates on arXiv.org
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Eugene Y. S. Chua, Craig Callender
Tue Mar 28 2023 09:16:27 (4 days)
# 12.
Programs in quantum gravity often claim that time emerges from fundamentally timeless physics. In the semiclassical time program time arises only after approximations are taken. Here we ask what justifies taking these approximations and show that time seems to sneak in when answering this question. This raises the worry that the approach is either unjustified or circular in deriving time from no-time.
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Mike D. Schneider
Tue Mar 28 2023 09:16:26 (4 days)
# 13.
I discuss empty space, as it appears in the physical foundations of relativistic field theories and in the semiclassical study of isolated systems. Of particular interest is the relationship between empirical measurements of the cosmological constant and the question of appropriate representation of empty space by spacetimes, or models of general relativity. Also considered is a speculative move that shows up in one corner of quantum gravity research. In pursuit of holographic quantum cosmology given a positive cosmological constant, there is evidently some freedom available for theoretical physicists to pick between two physically inequivalent spacetime representations of empty space, moving forward: de Sitter spacetime or its ‘elliptic’ cousin.
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physics.hist-ph updates on arXiv.org
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Mathias Van Den Bossche, Philippe Grangier
Tue Mar 28 2023 09:16:25 (4 days)
# 14.
Following an article by John von Neumann on infinite tensor products, we develop the idea that the usual formalism of quantum mechanics, associated with unitary equivalence of representations, stops working when countable infinities of particles (or degrees of freedom) are encountered. This is because the dimension of the corresponding Hilbert space becomes uncountably infinite, leading to the loss of unitary equivalence, and to sectorization. By interpreting physically this mathematical fact, we show that it provides a natural way to describe the “Heisenberg cut”, as well as a unified mathematical model including both quantum and classical physics, appearing as required incommensurable facets in the description of nature.
