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Fri Sep 01 2023 19:17:45 (17 hours)

# 1.

Wolf, William J. (2023) Cosmological Inflation and Meta-Empirical Theory Assessment. [Preprint]

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Raoni Arroyo, Jonas R. B. Arenhart, Décio Krause

Fri Sep 01 2023 09:34:23 (1 day)

# 2.

This chapter argues that the general philosophy of science should learn metaphilosophical lessons from the case of metaphysical underdetermination, as it occurs in non-relativistic quantum mechanics. Section 2 presents the traditional discussion of metaphysical underdetermination regarding the individuality and non-individuality of quantum particles. Section 3 discusses three reactions to it found in the literature: eliminativism about individuality; conservatism about individuality; eliminativism about objects. Section 4 wraps it all up with metametaphysical considerations regarding the epistemology of metaphysics of science.

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David Schmid, Yìlè Yīng, Matthew Leifer

Fri Sep 01 2023 09:34:20 (1 day)

# 3.

The Wigner’s friend thought experiment was intended to illustrate the difficulty one has in describing an agent as a quantum system when that agent performs a measurement. While it does pose a challenge to the orthodox interpretation of quantum theory, most modern interpretations have no trouble in resolving the difficulty. Recently, a number of extensions of Wigner’s ideas have been proposed. We provide a gentle introduction to six such arguments, modifying the specifics of many of them so that they are as simple and unified as possible. In particular, we show that all of the arguments hinge on assumptions about correlations between measurement outcomes that are not accessible to any observer, even in principle. We then provide a critical analysis of each argument, focusing especially on how well one can motivate the required assumptions regarding these inaccessible correlations. Although we argue that some of these assumptions are not entirely well-motivated, all of the arguments do shed light on the nature of quantum theory, especially when concerning the description of agents and their measurements. Although there are other possible responses, the most compelling of these no-go theorems can be taken to support the view that measurement outcomes are perspectival rather than absolute.

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Alan H. Guth, Mohammad Hossein Namjoo

Fri Sep 01 2023 09:34:19 (1 day)

# 4.

The two statistical methods, namely the frequentist and the Bayesian methods, are both commonly used for probabilistic inference in many scientific situations. However, it is not straightforward to interpret the result of one approach in terms of the concepts of the other. In this paper we explore the possibility of finding a Bayesian significance for the frequentist’s main object of interest, the $p$-value, which is the probability assigned to the proposition — which we call the {\it extremity proposition} — that a measurement will result in a value that is at least as extreme as the value that was actually obtained. To make contact with the frequentist language, the Bayesian can choose to update probabilities based on the {\it extremity proposition}, which is weaker than the standard Bayesian update proposition, which uses the actual observed value. We then show that the posterior probability (or probability density) of a theory is equal to the prior probability (or probability density) multiplied by the ratio of the $p$-value for the data obtained, given that theory, to the mean $p$-value — averaged over all theories weighted by their prior probabilities. Thus, we provide frequentist answers to Bayesian questions. Our result is generic — it does not rely on restrictive assumptions about the situation under consideration or specific properties of the likelihoods or the priors.

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Antoine Soulas

Fri Sep 01 2023 09:34:19 (1 day)

# 5.

Endeavoring to formulate an exhaustive solution to the measurement problem in view of the theory of decoherence leads to a better understanding of the status of the collapse and of the emergence of classicality, thanks to a precise definition of the measurement and some new vocabulary to speak about quantum mechanics. Considering the latter as a probabilistic theory all along allows us to avoid the usual probability problem of the many-worlds interpretations. A thorough verification of the consistency of quantum mechanics at all scales is proposed, as well as a discussion of what can be deemed an observer.

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Inge S. Helland

Fri Sep 01 2023 09:34:18 (1 day)

# 6.

An alternative approach towards quantum theory is described, and tentative attempts to connect his approach to special and general relativity are discussed. Important concepts are gauge groups and information/entropy connected to some physical systems. Some recent results on information in connection to black holes are touched upon.

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Carlo Branchina, Vincenzo Branchina, Filippo Contino, Arcangelo Pernace

Fri Sep 01 2023 09:34:11 (1 day)

# 7.

It has been recently proposed that we might live in a universe with a single compact extra dimension, whose mesoscopic size is dictated by the measured value of the cosmological constant. Central to this proposal is the result that in a $4+n$ dimensional theory with $n$ compact dimensions a tower of Kaluza-Klein (KK) states contributes an amount $m_{_{\rm KK}}^4$ to the vacuum energy $\rho_4$, where $m_{_{\rm KK}}$ is the KK scale of the tower. We show that the result $\rho_4 \sim m_{_{\rm KK}}^4$ comes from a mistreatment of the asymptotics of the loop momenta in the $4+n$ original theory. When the latter are correctly treated, new UV-sensitive terms appear in $\rho_4$ that invalidate the prediction of the dark dimension. We also show that, despite recent claims to the contrary, it is always possible to perform consistent effective field theory calculations that include only a finite number of tower states.

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Sunny Vagnozzi

Fri Sep 01 2023 09:34:07 (1 day)

# 8.

The Hubble tension has now grown to a level of significance which can no longer be ignored and calls for a solution which, despite a huge number of attempts, has so far eluded us. Significant efforts in the literature have focused on early-time modifications of $\Lambda$CDM, introducing new physics operating prior to recombination and reducing the sound horizon. In this opinion paper I argue that early-time new physics alone will always fall short of fully solving the Hubble tension. I base my arguments on seven independent hints, related to 1) the ages of the oldest astrophysical objects, 2) considerations on the sound horizon-Hubble constant degeneracy directions in cosmological data, 3) the important role of cosmic chronometers, 4) a number of “descending trends” observed in a wide variety of low-redshift datasets, 5) the early integrated Sachs-Wolfe effect as an early-time consistency test of $\Lambda$CDM, 6) early-Universe physics insensitive and uncalibrated cosmic standard constraints on the matter density, and finally 7) equality wavenumber-based constraints on the Hubble constant from galaxy power spectrum measurements. I argue that a promising way forward should ultimately involve a combination of early- and late-time (but non-local — in a cosmological sense, i.e. at high redshift) new physics, as well as local (i.e. at $z \sim 0$) new physics, and I conclude by providing reflections with regards to potentially interesting models which may also help with the $S_8$ tension.

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Fri Sep 01 2023 04:06:44 (1 day)

# 9.

Rivat, Sébastien (2023) Wait, Why Gauge? [Preprint]

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Fri Sep 01 2023 04:04:06 (1 day)

# 10.

Cuffaro, Michael E. (2023) The Measurement Problem Is a Feature, Not a Bug – Schematising the Observer as a Postulate and the Quantum-Mechanical Concept of an Open System on an Informational, or (neo-)Bohrian, Approach. [Preprint]

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Fri Sep 01 2023 03:56:56 (1 day)

# 11.

Miller, Ryan (2023) Chemical Reduction and Quantum Interpretation: A Case for Thomistic Emergence. Foundations of Chemistry. ISSN 1386-4238

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Gary T. Horowitz, Maciej Kolanowski, Grant N. Remmen, and Jorge E. Santos

Thu Aug 31 2023 18:00:00 (1 day)

# 12.

Author(s): Gary T. Horowitz, Maciej Kolanowski, Grant N. Remmen, and Jorge E. Santos

A theoretical analysis suggests that certain rotating black holes might be sensitive probes of quantum gravity.

[Phys. Rev. Lett. 131, 091402] Published Thu Aug 31, 2023

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Wed Aug 30 2023 19:47:27 (2 days)

# 13.

Rubin, Mark (2023) The replication crisis is less of a “crisis” in the Lakatosian approach than it is in the Popperian and naïve methodological falsificationism approaches. [Preprint]

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Wed Aug 30 2023 19:41:11 (2 days)

# 14.

Rickles, Dean and Elshatlawy, Hatem and Arsiwalla, Xerxes (2023) Ruliology: Linking Computation, Observers and Physical Law. [Preprint]

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David J. Tannor

Wed Aug 30 2023 12:04:05 (3 days)

# 15.

In 1834-1835, Hamilton published two papers that revolutionized classical mechanics. In these papers, he introduced the Hamilton-Jacobi equation, Hamilton’s equations of motion and the principle of least action. These three formulations of classical mechanics became the forerunners of quantum mechanics, but none of these is what Hamilton was looking for: he was looking for what he called the principal function, $S(q’,q”,T)$, from which the entire trajectory history can be obtained just by differentiation. Here we show that all of Hamilton’s formulations can be derived just by assuming that the principal function is additive, $S(q’,q”,T)=S(q’,Q,t_1)+S(Q,q”,t_2)$ with $t_1+t_2=T$. This simple additivity axiom can be considered the fundamental principle of classical mechanics and shows that analytical mechanics is essentially just a footnote to the problem of finding the shortest path between two points. The simplicity of the formulation could provide new perspectives on some of the major themes in classical mechanics including symplectic geometry, periodic orbit theory and Morse theory, as well as giving new perspectives on quantum mechanics. Moreover, it could potentially provide a unified description of different areas of physics, leading to insight for example, into the transition from deterministic dynamics to statistical mechanics.

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Wed Aug 30 2023 07:01:26 (3 days)

# 16.

Coko, Klodian (2023) Controlling the Invisible: Experimental Strategies and Hypotheses in Discovering the Cause of Brownian Movement. [Preprint]

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Tue Aug 29 2023 02:05:03 (4 days)

# 17.

Stoica, Ovidiu Cristinel (2023) Asking physics about physicalism, zombies, and consciousness. [Preprint]

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Tue Aug 29 2023 02:02:28 (4 days)

# 18.

Struyve, Ward (2023) Scope of the action principle. [Preprint]

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Daniel Linford

Mon Aug 28 2023 10:00:52 (5 days)

# 19.

Intuitively, the totality of physical reality — the Cosmos — has a beginning only if (i) all parts of the Cosmos agree on the direction of time (the Direction Condition) and (ii) there is a boundary to the past of all non-initial spacetime points such that there are no spacetime points to the past of the boundary (the Boundary Condition). Following a distinction previously introduced by J. Brian Pitts, the Boundary Condition can be conceived of in two distinct ways: either topologically, i.e., in terms of a closed boundary, or metrically, i.e., in terms of the Cosmos having a finite past. This article proposes that the Boundary Condition should be posed disjunctively, modifies and improves upon the metrical conception of the Cosmos’s beginning in light of a series of surprising yet simple thought experiments, and suggests that the Direction and Boundary Conditions should be thought of as more fundamental to the concept of the Cosmos’s beginning than classical Big Bang cosmology.

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Mon Aug 28 2023 04:26:05 (5 days)

# 20.

March, Eleanor (2023) Are Maxwell gravitation and Newton-Cartan theory theoretically equivalent? [Preprint]