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Sun Jul 07 2024 12:08:42 (22 hours)
# 1.
Ross, Lauren N. and Jirsa, Viktor and McIntosh, Anthony (2024) The Possibility Space Concept in Neuroscience: Possibilities, Constraints, and Explanation. [Preprint]
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Sun Jul 07 2024 06:21:19 (1 day)
# 2.
Horvat, Sebastian and Toader, Iulian D. (2023) An Alleged Tension Between non-Classical Logics and Applied Classical Mathematics. [Preprint]
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Sun Jul 07 2024 06:21:04 (1 day)
# 3.
Horvat, Sebastian and Toader, Iulian D. (2023) Quantum logic and meaning. [Preprint]
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Sat Jul 06 2024 07:16:39 (2 days)
# 4.
Cheng, Bryan and Read, James (2024) The Hole Argument and Putnam’s Paradox. [Preprint]
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Sat Jul 06 2024 07:16:10 (2 days)
# 5.
ROVELLI, Carlo (2024) Princeton seminars on physics and philosophy. [Preprint]
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Jordan Scharnhorst, David Wolpert, Carlo Rovelli
Thu Jul 04 2024 12:25:39 (3 days)
# 6.
arXiv:2407.02840v1 Announce Type: cross Abstract: It is often stated that the second law of thermodynamics follows from the condition that at some given time in the past the entropy was lower than it is now. Formally, this condition is the statement that $E[S(t)|S(t_0)]$, the expected entropy of the universe at the current time $t$ conditioned on its value $S(t_0)$ at a time $t_0$ in the past, is an increasing function of $t $. We point out that in general this is incorrect. The epistemic axioms underlying probability theory say that we should condition expectations on all that we know, and on nothing that we do not know. Arguably, we know the value of the universe’s entropy at the present time $t$ at least as well as its value at a time in the past, $t_0$. However, as we show here, conditioning expected entropy on its value at two times rather than one radically changes its dynamics, resulting in a unexpected, very rich structure. For example, the expectation value conditioned on two times can have a maximum at an intermediate time between $t_0$ and $t$, i.e., in our past. Moreover, it can have a negative rather than positive time derivative at the present. In such “Boltzmann bridge” situations, the second law would not hold at the present time. We illustrate and investigate these phenomena for a random walk model and an idealized gas model, and briefly discuss the role of Boltzmann bridges in our universe.
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Eftychios Kaimakkamis, Karunava Sil
Thu Jul 04 2024 12:25:28 (3 days)
# 7.
arXiv:2407.03077v1 Announce Type: new Abstract: We study ambiguities in the precise formulation of the Wheeler-DeWitt equation for the wavefunction of the Universe that arise due to different operator orderings in the quantum Hamiltonian. We first examine the simpler case of the 1-dimensional minisuperspace model and derive the inner product measure that renders the Hamiltonian hermitian. Based on this, we establish that the Hilbert space inner products and quantum probabilities are universal, free of any ambiguities, at the semiclassical level. Recasting the Wheeler-DeWitt equation in a form invariant under field redefinitions of the minisuperspace variable, we show that all ambiguity functions are contained in a higher order scalar function, which can be used to define classes of models with universal predictions to all orders in $\hbar$. We then generalize to minisuperspace models of arbitrary dimension, upon the inclusion of an arbitrary number of scalar matter fields. We show that the hermiticity of the Hamiltonian in these cases provides a set of constraints, which can be used to cast the WDW equation in a covariant form and establish the universality of the inner products at the semiclassical level. In these cases as well, all ambiguity functions appear in a higher order scalar function of the minisuperspace manifold, which leads to distinct universality classes.
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Daine L. Danielson, Gautam Satishchandran, Robert M. Wald
Thu Jul 04 2024 12:25:26 (3 days)
# 8.
arXiv:2407.02567v1 Announce Type: cross Abstract: It was previously shown that if an experimenter, Alice, puts a massive or charged body in a quantum spatial superposition, then the presence of a black hole (or more generally any Killing horizon) will eventually decohere the superposition [arXiv:2205.06279, arXiv:2301.00026, arXiv:2311.11461]. This decoherence was identified as resulting from the radiation of soft photons/gravitons through the horizon, thus suggesting that the global structure of the spacetime is essential for describing the decoherence. In this paper, we show that the decoherence can alternatively be described in terms of the local two-point function of the quantum field within Alice’s lab, without any direct reference to the horizon. From this point of view, the decoherence of Alice’s superposition in the presence of a black hole arises from the extremely low frequency Hawking quanta present in Alice’s lab. We explicitly calculate the decoherence occurring in Schwarzschild spacetime in the Unruh vacuum from the local viewpoint. We then use this viewpoint to elucidate (i) the differences in decoherence effects that would occur in Schwarzschild spacetime in the Boulware and Hartle-Hawking vacua; (ii) the difference in decoherence effects that would occur in Minkowski spacetime filled with a thermal bath as compared with Schwarzschild spacetime; (iii) the lack of decoherence in the spacetime of a static star even though the vacuum state outside the star is similar in many respects to the Boulware vacuum around a black hole; and (iv) the requirements on the degrees of freedom of a material body needed to produce a decoherence effect that mimics that of a black hole.
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Casper van Elteren
Thu Jul 04 2024 10:06:23 (4 days)
# 9.
arXiv:2407.01762v1 Announce Type: new Abstract: From bird flocking to neural dynamics, complex systems generate fascinating structures and correlations. Often, seemingly simple dynamics lead to intricate emergent properties. Despite their visceral appeal, defining complex systems lacks universal agreement. In this paper, I will debunk three prevalent myths in complex systems and propose resolutions. This work contributes by offering a contemporary interpretation of complex systems, presenting essential definitions that benefit complexity scientists.
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Ovidiu Cristinel Stoica
Thu Jul 04 2024 10:06:21 (4 days)
# 10.
arXiv:2407.02421v1 Announce Type: cross Abstract: I show that, by the same criteria that led to Galilean and Special Relativity and gauge symmetries, there is no way to identify a unique set of observables that give the structure of space or spacetime. In some sense, space is lost in the state space itself. Moreover, the relationship between the observables and the physical properties they represent becomes relative. But we can verify that they are not relative, and the spacetime structure is unique. I show that this implies that not all structures isomorphic with observers can be observers, contradicting Structural Realism and Physicalism. This indicates a strong connection between spacetime and the sentience of the observers, as anticipated by some early contributors to Special and General Relativity.
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A. Rod Gover, Jarosław Kopiński, and Andrew Waldron
Wed Jul 03 2024 18:00:00 (4 days)
# 11.
Author(s): A. Rod Gover, Jarosław Kopiński, and Andrew Waldron
We develop the mathematics needed to treat the interaction of geometry and stress at any isotropic spacetime singularity. This enables us to handle the Einstein equations at the initial singularity and characterize allowed general relativistic stress-energy tensors. Their leading behaviors are dicta…
[Phys. Rev. Lett. 133, 011401] Published Wed Jul 03, 2024
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Tue Jul 02 2024 18:07:14 (5 days)
# 12.
Ryoo, Hong Joo (2024) On Functionalism’s Context-Dependent Explanations of Mental States. [Preprint]
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Tue Jul 02 2024 18:06:56 (5 days)
# 13.
Wray, K. Brad (2024) Influences on Kuhn and the Relationship between History and Philosophy of Science. In: UNSPECIFIED.
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Tue Jul 02 2024 18:00:42 (5 days)
# 14.
Mulder, Ruward A. (2024) The Classical Stance: Dennett’s Criterion in Wallacian quantum mechanics. Studies in History and Philosophy of Science. ISSN 00393681
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Tue Jul 02 2024 18:00:09 (5 days)
# 15.
Patton, Lydia (2024) Kuhn-Loss, Persuasion, and Incommensurability Again – Can Paradigm-Change be Rationally Justified? In: UNSPECIFIED.
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Tue Jul 02 2024 17:59:37 (5 days)
# 16.
March, Eleanor and Wolf, William J. and Read, James (2024) On the geometric trinity of gravity, non-relativistic limits, and Maxwell gravitation. [Preprint]
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Charles T. Sebens
Tue Jul 02 2024 12:06:02 (5 days)
# 17.
arXiv:2407.00210v1 Announce Type: new Abstract: The view that the laws of nature produce later states of the universe from earlier ones (prominently defended by Maudlin) faces difficult questions as to how the laws produce the future and whether that production is compatible with special relativity. This article grapples with those questions, arguing that the concerns can be overcome through a close analysis of the laws of classical mechanics and electromagnetism. The view that laws produce the future seems to require that the laws of nature take a certain form, fitting what Adlam has called “the time evolution paradigm.” Making that paradigm precise, we might demand that there be temporally local dynamical laws that take properties of the present and the arbitrarily-short past as input, returning as output changes in such properties into the arbitrarily-short future. In classical mechanics, Newton’s second law can be fit into this form if we follow a proposal from Easwaran and understand the acceleration that appears in the law to capture how velocity (taken to be a property of the present and the arbitrarily-short past) changes into the arbitrarily-short future. The dynamical laws of electromagnetism can be fit into this form as well, though because electromagnetism is a special relativistic theory we might require that the laws meet a higher standard: linking past light-cone to future light-cone. With some work, the laws governing the evolution of the vector and scalar potentials, as well as the evolution of charged matter, can be put in a form that meets this higher standard.
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Michael J. W. Hall
Mon Jul 01 2024 12:10:13 (6 days)
# 18.
arXiv:2406.19426v1 Announce Type: cross Abstract: Does determinism (or even the incompleteness of quantum mechanics) follow from locality and perfect correlations? In a 1964 paper John Bell gave the first demonstration that quantum mechanics is incompatible with local hidden variables. Since then a vigorous debate has rung out over whether he relied on an assumption of determinism or instead, as he later claimed in a 1981 paper, derived determinism from assumptions of locality and perfect correlation. This paper aims to bring clarity to the debate via simple examples and rigorous results. It is first recalled, via quantum and classical counterexamples, that the weakest statistical form of locality consistent with Bell’s 1964 paper (parameter independence) is insufficient for the derivation of determinism. Attention is then turned to critically assess Bell’s appealing to the Einstein-Rosen-Podolsky incompleteness argument to support his claim. It is shown this argument is itself incomplete, via counterexamples that expose two logical gaps. However, closing these gaps via a strong “counterfactual” reality criterion enables a rigorous derivation of each of quantum incompleteness, determinism and parameter independence, and in this sense justifies Bell’s claim. Consequences for quantum interpretations are briefly discussed.
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Debarchan Das
Mon Jul 01 2024 08:00:00 (1 week)
# 19.
Nature Physics, Published online: 01 July 2024; doi:10.1038/s41567-024-02581-2A Journey from Earth to Venus to Mars
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Sun Jun 30 2024 06:13:45 (1 week)
# 20.
Arroyo, Raoni Wohnrath and NUNES FILHO, LAURO DE MATOS and MOREIRA DOS SANTOS, FREDERIK (2024) Towards a process-based approach to consciousness and collapse in quantum mechanics. Manuscrito, 47 (1). ISSN 0100-6045
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Sat Jun 29 2024 12:52:26 (1 week)
# 21.
Allori, Valia (2024) Quantum Ontology and Intuitions. [Preprint]
# 22.
Schrodinger’s Cat: Qbit or Cbit?
Stuckey, W. M. (2024) Schrodinger’s Cat: Qbit or Cbit? [Preprint]
Abstract: In 1935, Schrodinger introduced what he considered to be a reductio against the Copenhagen interpretation of quantum mechanics. His argument was based on a “ridiculous case” that is widely used today to portray the counterintuitive nature of quantum superposition. Schrodinger imagined that a cat was placed out of sight in a box with a mechanism that would kill the cat within an hour with 50% probability. Since the deadly mechanism employed a quantum process for its trigger, he supposed the cat was in a quantum superposition of 50% Live Cat + 50% Dead Cat. In this paper, we point out that if Schrodinger’s Cat actually represents a quantum superposition of 50% Live Cat + 50% Dead Cat, as is commonly asserted, then the cat-box system is the physical instantiation of a quantum bit of information (Qbit). This agrees with the Copenhagen interpretation, which says there is no fact of the matter as to whether the cat is dead or alive until a measurement is made. Accordingly, the state 50% Live Cat + 50% Dead Cat must be the outcome with 100% probability for some measurement complementary to the measurement ‘open the box’ with its two possible measurement outcomes of Live Cat or Dead Cat. If one cannot provide a physically meaningful complementary measurement to ‘open the box’ with a clear empirical consequence represented by the state 50% Live Cat + 50% Dead Cat as its (certain) measurement outcome, then the state 50% Live Cat + 50% Dead Cat only represents a distribution of outcomes for many trials of that single ‘open the box’ measurement. That is, the state 50% Live Cat + 50% Dead Cat is not a quantum superposition and Schrodinger’s Cat is merely the physical instantiation of a classical bit of information (Cbit) in support of Schrodinger’s reductio. The double-slit experiment is provided as an example of a Qbit to illustrate what is meant by complementary measurements (position x and momentum p for the double-slit experiment).
