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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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Sandro Donadi, Luca Ferialdi, and Angelo Bassi

Fri Jun 09 2023 18:00:00 (15 hours)

# 1.

Author(s): Sandro Donadi, Luca Ferialdi, and Angelo Bassi

Noninterferometric experiments have been successfully employed to constrain models of spontaneous wave function collapse, which predict a violation of the quantum superposition principle for large systems. These experiments are grounded on the fact that, according to these models, the dynamics is dr…

[Phys. Rev. Lett. 130, 230202] Published Fri Jun 09, 2023

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Fri Jun 09 2023 00:50:32 (1 day)

# 2.

Zhao, Kino (2023) Measuring the non-existent: validity before measurement. Philosophy of Science, 90 (2). pp. 227-244.

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Fri Jun 09 2023 00:50:06 (1 day)

# 3.

Hunt, Josh and Carcassi, Gabriele and Aidala, Christine A (2023) Hamiltonian Privilege. [Preprint]

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Geraint F. Lewis, Brendon J. Brewer

Thu Jun 08 2023 16:24:59 (1 day)

# 4.

A fundamental prediction of relativistic cosmologies is that, due to the expansion of space, observations of the distant cosmos should be time dilated and appear to run slower than events in the local universe. Whilst observations of cosmological supernovae unambiguously display the expected redshift-dependent time dilation, this has not been the case for other distant sources. Here we present the identification of cosmic time dilation in a sample of 190 quasars monitored for over two decades in multiple wavebands by assessing various hypotheses through Bayesian analysis. This detection counters previous claims that observed quasar variability lacked the expected redshift-dependent time dilation. Hence, as well as demonstrating the claim that the lack of the redshift dependence of quasar variability represents a significant challenge to the standard cosmological model, this analysis further indicates that the properties of quasars are consistent with them being truly cosmologically distant sources.

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Andrzej Grudka, Jȩdrzej Stempin, Jan Wójcik, Antoni Wójcik

Thu Jun 08 2023 16:24:59 (1 day)

# 5.

The quantum description of reality is quite different from the classical one. Understanding this difference at a fundamental level is still an interesting topic. Recently, Dragan and Ekert [New J. Phys. 22 (2020) 033038] postulated that considering so-called superluminal observers can be useful in this context. In particular, they claim that the full mathematical structure of the generalized Lorentz transformation may imply the emergence of multiple quantum mechanical trajectories. On the contrary, here we show that the generalized Lorentz transformation, when used in a consistent way, does not provide any correspondence between the classical concept of a definite path and the multiple paths of quantum mechanics.

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Sarbari Guha

Thu Jun 08 2023 16:24:55 (1 day)

# 6.

The concept of entropy forms the backbone of the principles of thermodynamics. R.C. Tolman initiated a correlation between gravity and thermodynamics. The development of black hole thermodynamics and the generalized second law of thermodynamics led to Penrose’s conjecture that the Weyl tensor should serve as a measure of the entropy of the free gravitational field. This entropy reflects the degrees of freedom associated with the free gravitational field. The proposition of gravitational entropy justifies the initial entropy of the universe. This entropy function had to be associated with the dynamics of the free gravitational field from the time of the big bang, so that a gravity-dominated evolution of the universe preserves the second law of thermodynamics. Moreover, the concept of black hole entropy emerges as a particular case of the entropy of the free gravitational field. However, a self-consistent notion of gravitational entropy in the context of cosmological structure formation has eluded us till today. Various proposals have been put forward, initially based on Penrose’s Weyl Curvature Hypothesis, and subsequently modified to fit the needs of specific geometries and matter distributions. Such proposals were basically geometric in nature. A few years back a new definition of gravitational entropy was proposed from the considerations of the relativistic Gibb’s equation and based on the square root of the Bel-Robinson tensor, the simplest divergence-free tensor derived from the Weyl tensor. Even this proposal is valid only for a restricted class of spacetimes. A complete self-consistent description of gravitational entropy encompassing black hole physics and cosmological dynamics is yet to emerge. In this article, we gather an overview of the concept of gravitational entropy, following it up with the development of the various proposals of gravitational entropy.

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Thu Jun 08 2023 00:37:06 (2 days)

# 7.

Kjærsdam Telléus, Emilia (2022) Measuring up to the Measurement Problem: Decoherence and Bohr’s ideas through the lens of the measurement problem and quantum erasers. [Preprint]

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Thu Jun 08 2023 00:23:10 (2 days)

# 8.

Belot, Gordon (2023) Unprincipled. [Preprint]

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physics.hist-ph updates on arXiv.org

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Paul Tappenden

Wed Jun 07 2023 09:00:13 (3 days)

# 9.

The 2022 Tel Aviv conference on the Many Worlds interpretation of quantum mechanics highlighted many differences between theorists. A very significant dichotomy is between Everettian fission (splitting) and Saunders-Wallace-Wilson divergence. For fission, an observer may have multiple futures, whereas for divergence they always have a single future. Divergence was explicitly introduced to resolve the problem of pre-measurement uncertainty for Everettian theory, which is universally believed to be absent for fission. Here, I maintain that there is indeed uncertainty about future observations prior to fission, so long as objective probability is a property of Everettian branches. This is made possible if the universe is a set and branches are subsets with probability measure. A universe which is a set of universes which are macroscopically isomorphic and span all possible configurations of microscopic local be\”ables fulfils that role. If objective probability is a property of branches, a successful Deutsch-Wallace decision-theoretic argument would justify the Principal Principle and be part of probability theory rather than being specific to Many Worlds. Any macroscopic object in our environment becomes a set of isomorphs with different microscopic configurations, each in an elemental universe (elemental in the set-theoretic sense). This is similar to Many Interacting Worlds theory but the observer inhabits the set of worlds, not an individual world. An observer has many elemental bodies.

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physics.hist-ph updates on arXiv.org

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Marius Krumm, Markus P. Mueller

Wed Jun 07 2023 09:00:12 (3 days)

# 10.

Can free agency be compatible with determinism? Compatibilists argue that the answer is yes, and it has been suggested that the computer science principle of “computational irreducibility” sheds light on this compatibility. It implies that there cannot in general be shortcuts to predict the behavior of agents, explaining why deterministic agents often appear to act freely. In this paper, we introduce a variant of computational irreducibility that intends to capture more accurately aspects of actual (as opposed to apparent) free agency: computational sourcehood, i.e. the phenomenon that the successful prediction of a process’ behavior must typically involve an almost-exact representation of the relevant features of that process, regardless of the time it takes to arrive at the prediction. We argue that this can be understood as saying that the process itself is the source of its actions, and we conjecture that many computational processes have this property. The main contribution of this paper is technical: we analyze whether and how a sensible formal definition of computational sourcehood is possible. While we do not answer the question completely, we show how it is related to finding a particular simulation preorder on Turing machines, we uncover concrete stumbling blocks towards constructing such a definition, and demonstrate that structure-preserving (as opposed to merely simple or efficient) functions between levels of simulation play a crucial role.

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Tue Jun 06 2023 23:36:04 (3 days)

# 11.

Ketland, Jeffrey (2023) Equivalent Axiomatizations of Euclidean Geometry. [Preprint]

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Tue Jun 06 2023 23:35:11 (3 days)

# 12.

Yasmineh, Salim (2023) Non-local Building Blocks of Spacetime. [Preprint]

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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

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John H. Selby, David Schmid, Elie Wolfe, Ana Belén Sainz, Ravi Kunjwal, and Robert W. Spekkens

Tue Jun 06 2023 18:00:00 (3 days)

# 13.

Author(s): John H. Selby, David Schmid, Elie Wolfe, Ana Belén Sainz, Ravi Kunjwal, and Robert W. Spekkens

The existence of incompatible measurements is often believed to be a feature of quantum theory which signals its inconsistency with any classical worldview. To prove the failure of classicality in the sense of Kochen-Specker noncontextuality, one does indeed require sets of incompatible measurements…

[Phys. Rev. Lett. 130, 230201] Published Tue Jun 06, 2023

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Tue Jun 06 2023 01:44:29 (4 days)

# 14.

Kashyap, Abhishek (2023) General Relativity, MOND, and the problem of unconceived alternatives. [Preprint]

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physics.hist-ph updates on arXiv.org

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G. J. Milburn, S. Shrapnel, P. W. Evans

Mon Jun 05 2023 08:55:27 (5 days)

# 15.

We ground the asymmetry of causal relations in the internal physical states of a special kind of open and irreversible physical system, a causal agent. A causal agent is an autonomous physical system, maintained in a steady state, far from thermal equilibrium, with special subsystems: sensors, actuators, and learning machines. Using feedback, the learning machine, driven purely by thermodynamic constraints, changes its internal states to learn probabilistic functional relations inherent in correlations between sensor and actuator records. We argue that these functional relations just are causal relations learned by the agent, and so such causal relations are simply relations between the internal physical states of a causal agent. We show that learning is driven by a thermodynamic principle: the error rate is minimised when the dissipated power is minimised. While the internal states of a causal agent are necessarily stochastic, the learned causal relations are shared by all machines with the same hardware embedded in the same environment. We argue that this dependence of causal relations on such `hardware’ is a novel demonstration of causal perspectivalism.

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physics.hist-ph updates on arXiv.org

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Michael E. Cuffaro, Stephan Hartmann

Mon Jun 05 2023 08:55:26 (5 days)

# 16.

There is a deeply entrenched view in philosophy and physics, the closed systems view, according to which isolated systems are conceived of as fundamental. On this view, when a system is under the influence of its environment this is described in terms of a coupling between it and a separate system which taken together are isolated. We argue against this view, and in favor of the alternative open systems view, for which systems interacting with their environment are conceived of as fundamental, and the environment’s influence is represented via the dynamical equations that govern the system’s evolution. Taking quantum theories of closed and open systems as our case study, and considering three alternative notions of fundamentality: (i)~ontic fundamentality, (ii)~epistemic fundamentality, and (iii)~explanatory fundamentality, we argue that the open systems view is fundamental, and that this has important implications for the philosophy of physics, the philosophy of science, and for metaphysics.