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Roderich Tumulka

Fri Sep 13 2024 12:00:00 (1 day)

# 1.

arXiv:2409.07784v1 Announce Type: new Abstract: Despite many successes of quantum electrodynamics (QED), we do not presently have a good understanding of this field of physics. QED has all of the foundational problems that standard non-relativistic quantum mechanics has, and further ones in addition. I discuss some of these problems and some options for what a Bohm-style theory of QED, with an ontology in space and time, could look like. I also point out why the proposal made by Bohm himself in 1952 for QED is not quite convincing. Finally, I outline the kind of Bohm-type theory of QED that I would consider convincing, and report about recent progress toward this kind of theory.

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Gabriel Fernandez Ferrari, {\L}ukasz Rudnicki, Lucas Chibebe C\’eleri

Fri Sep 13 2024 12:00:00 (1 day)

# 2.

arXiv:2409.07676v1 Announce Type: new Abstract: Thermodynamics is based on a coarse-grained approach, from which its fundamental variables emerge, effectively erasing the complicate details of the microscopic dynamics within a macroscopic system. The strength of Thermodynamics lies in the universality provided by this paradigm. In contrast, quantum mechanics focuses on describing the dynamics of microscopic systems, aiming to make predictions about experiments we perform, a goal shared by all fundamental physical theories, which are often framed as gauge theories in modern physics. Recently, a gauge theory for quantum thermodynamics was introduced, defining gauge invariant work and heat, and exploring their connections to quantum phenomena. In this work, we extend that theory in two significant ways. First, we incorporate energy spectrum degeneracies, which were previously overlooked. Additionally, we define gauge-invariant entropy, exploring its properties and connections to other physical and informational quantities. This results in a complete framework for quantum thermodynamics grounded in the principle of gauge invariance. To demonstrate some implications of this theory, we apply it to well-known critical systems.

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M. S. Guimaraes, I. Roditi, S. P. Sorella

Fri Sep 13 2024 12:00:00 (1 day)

# 3.

arXiv:2409.07597v1 Announce Type: new Abstract: A pedagogical introduction to Bell’s inequality in Quantum Mechanics is presented. Several examples, ranging from spin $1/2$ to coherent and squeezed states are worked out. The generalization to Mermin’s inequalities and to GHZ states is also outlined.

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Laurens Walleghem, Y\`il\`e Y\=ing, Rafael Wagner, David Schmid

Fri Sep 13 2024 12:00:00 (1 day)

# 4.

arXiv:2409.07537v1 Announce Type: new Abstract: The Local Friendliness argument is an extended Wigner’s friend no-go theorem that provides strong constraints on the nature of reality — stronger even than those imposed by Bell’s theorem or by noncontextuality arguments. In this work, we prove a variety of connections between Local Friendliness scenarios and Kochen-Specker noncontextuality. Specifically, we first show how one can derive new Local Friendliness inequalities using known tools and results from the literature on Kochen-Specker noncontextuality. In doing so, we provide a new derivation for some of the facets of the Local Friendliness polytope, and we prove that this polytope is equal to the Bell polytope in a wide range of extended Wigner’s friend scenarios with multipartite agents and sequential measurements. We then show how any possibilistic Kochen-Specker argument can be mathematically translated into a related proof of the Local Friendliness no-go theorem. In particular, we construct a novel kind of Local Friendliness scenario where a friend implements several compatible measurements (or joint measurements of these) in between the superobserver’s operations on them. We illustrate this with the well-known 5-cycle and Peres-Mermin contextuality arguments.

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Fri Sep 13 2024 00:56:00 (1 day)

# 5.

March, Eleanor and Read, James (2024) A primer on Carroll gravity. [Preprint]

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Fri Sep 13 2024 00:53:38 (1 day)

# 6.

Callender, Craig (2023) Temporal Neutrality Implies Exponential Temporal Discounting. Philosophy of Science, 90 (5).

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Fri Sep 13 2024 00:52:22 (1 day)

# 7.

Callender, Craig (2024) Insights into Quantum Time Reversal from the Classical Schrödinger Equation. [Preprint]

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Fri Sep 13 2024 00:51:22 (1 day)

# 8.

Read, James (2024) Review of “Logic Meets Wigner’s Friend (and their Friends)”, by Alexandru Baltag and Sonja Smets. [Preprint]

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Fri Sep 13 2024 00:49:32 (1 day)

# 9.

Fortin, Sebastian and Pasqualini, Matias (2024) Emergence-Free Duality: Phonons and Vibrating Atoms in Crystalline Solids. [Preprint]

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Fri Sep 13 2024 00:48:34 (1 day)

# 10.

Gao, Shan (2024) Simplest Quantum Mechanics: Why It Is Better Than Bohmian, Everettian and Collapse Theories. [Preprint]

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Thu Sep 12 2024 01:00:21 (2 days)

# 11.

Broka, Chris A. (2024) Degenerate States and the Problem of Quantum Measurement. [Preprint]

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Thu Sep 12 2024 00:59:05 (2 days)

# 12.

Di Biagio, Andrea and Rovelli, Carlo (2024) On the Time Orientation of Probabilistic Theories. [Preprint]

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Wed Sep 11 2024 05:30:44 (3 days)

# 13.

Toader, Iulian Danut (2024) Weyl’s Quantifiers. [Preprint]

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Toby Peterken

Tue Sep 10 2024 12:00:00 (4 days)

# 14.

arXiv:2307.16531v2 Announce Type: replace Abstract: In this work, we attempt to define a notion of compositeness compatible with Quantum Field Theory. Considering the analytic properties of the S-matrix, we conclude that there is no satisfactory definition of compositeness compatible with Quantum Field Theory. Without this notion, one must claim that all bound states are equally fundamental, that is, one cannot rigorously claim that everyday objects are made of atoms or that atoms are made of protons and neutrons. I then show how an approximate notion of compositeness may be recovered in the regime where the mass of a bound state is close to a multi-particle threshold. Finally, we see that rejecting compositeness solves several of the “problems of everyday objects” encountered in an undergraduate metaphysics course.

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Emily Adlam

Tue Sep 10 2024 12:00:00 (4 days)

# 15.

arXiv:2409.05259v1 Announce Type: new Abstract: I distinguish between pure self-locating credences and superficially self-locating credences, and argue that there is never any rationally compelling way to assign pure self-locating credences. I first argue that from a practical point of view, pure self-locating credences simply encode our pragmatic goals, and thus pragmatic rationality does not dictate how they must be set. I then use considerations motivated by Bertrand’s paradox to argue that the indifference principle and other popular constraints on self-locating credences fail to be a priori principles of epistemic rationality, and I critique some approaches to deriving self-locating credences based on analogies to non-self-locating cases. Finally, I consider the implications of this conclusion for various applications of self-locating probabilities in scientific contexts, arguing that it may undermine certain kinds of reasoning about multiverses, the simulation hypothesis, and Boltzmann brains.

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Mario Bacelar Valente

Tue Sep 10 2024 12:00:00 (4 days)

# 16.

arXiv:2409.04450v1 Announce Type: new Abstract: With special relativity, we seem to be facing a conundrum. It is a very well-tested theory; in this way, the Minkowski spacetime must be “capturing” essential features of space and time. However, its geometry seems to be incompatible with any sort of global notion of time. We might only have local notions of now (present moment) and time flow, at best. In this note, we will explore the possibility that a pretty much global notion of now (and time flow) might be hiding in plain sight in the geometry of the Minkowski spacetime.

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Tue Sep 10 2024 00:42:41 (4 days)

# 17.

Wallace, David (2024) Real Patterns in Physics and Beyond. [Preprint]

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D V Red\v{z}i\’c

Mon Sep 09 2024 12:00:00 (5 days)

# 18.

arXiv:2404.19566v2 Announce Type: replace-cross Abstract: The complex relationship between Einstein’s second postulate and the Maxwell electromagnetic theory is elucidated. A simple deduction of the main results of the Ignatowski approach to the theory of relativity is given. The peculiar status of the principle of relativity among the Maxwellians is illustrated.

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Alejandro Cassini, Leonardo Levinas

Mon Sep 09 2024 12:00:00 (5 days)

# 19.

arXiv:2407.12960v2 Announce Type: replace Abstract: We elucidate how different theoretical assumptions bring about radically different interpretations of the same experimental result. We do this by analyzing special relativity as it was originally formulated. Then, we examine the relationship of the theory with the result of the Michelson and Morley experiment. We point out that in diverse a historical context the same experiment can be thought of as providing different conceptualizations of phenomena. This demonstrates why special relativity prevailed over its rival theories. This theory made a new reinterpretation of the experiment by associating it with a novel phenomenon, namely, the invariance of the speed of light, a phenomenon that was not the one originally investigated. This leads us to an understanding of how this experiment could have been interpreted in a completely different historical context.

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Leonardo Levinas

Mon Sep 09 2024 12:00:00 (5 days)

# 20.

arXiv:2304.06860v2 Announce Type: replace Abstract: In the famous thought experiment studied in this article, Galileo attempted to refute the Aristotelian hypothesis that heavier bodies should fall more quickly than lighter ones. After pointing out some inconsistencies in Galileo’s approach, we show, through the design of two alternative but equivalent experiments, that from his imaginary experiment, it is not possible to reach the conclusion that all bodies fall simultaneously. We show why, to explain the result of this type of experience, it is necessary to establish the equivalence between inertial and gravitational masses derived exclusively from experience.

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Aur\’elien Drezet

Mon Sep 09 2024 12:00:00 (5 days)

# 21.

arXiv:2409.04304v1 Announce Type: cross Abstract: In this work we analyze recent proposals by Das and D\”{u}rr (DD) to measure the arrival time distributions of quantum particles within the framework of de Broglie Bohm theory (or Bohmian mechanics). We also analyze the criticisms made by Goldstein Tumulka and Zangh\`{i} (GTZ) of these same proposals, and show that each protagonist is both right and wrong. In fine, we show that DD’s predictions are indeed measurable in principle, but that they will not lead to violations of the no-signalling theorem used in Bell’s theorem, in contradiction with some of Das and Maudlin’s hopes.

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Sun Sep 08 2024 00:44:32 (6 days)

# 22.

Vergouwen, Sanne and De Haro, Sebastian (2024) Supersymmetry in the Seiberg-Witten Theory: A Window into Quantum Field Theory. [Preprint]

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Sun Sep 08 2024 00:43:31 (6 days)

# 23.

Hashemi, Ataollah (2024) A Panpsychist Solution to the Exclusion Problem. Acta Analytica.

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Sun Sep 08 2024 00:41:53 (6 days)

# 24.

Elder, Jamee (2023) On the “Direct Detection” of Gravitational Waves. [Preprint]

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Sun Sep 08 2024 00:41:07 (6 days)

# 25.

Klein, Ulf (2024) Quantizing Galilean spacetime: a reconstruction of Maxwell’s equations in empty space. Quantum Stud. : Math. Found., 11. pp. 717-737.

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Ramon Jose C. Bagunu, Eric A. Galapon

Sat Sep 07 2024 12:00:00 (1 week)

# 26.

arXiv:2409.03348v1 Announce Type: new Abstract: One of the fundamental problems in quantum mechanics is finding the correct quantum image of a classical observable that would correspond to experimental measurements. We investigate for the appropriate quantization rule that would yield a Hamiltonian that obeys the quantum analogue of Hamilton’s equations of motion, which includes differentiation of operators with respect to another operator. To give meaning to this type of differentiation, Born and Jordan established two definitions called the differential quotients of first type and second type. In this paper we modify the definition for the differential quotient of first type and establish its consistency with the differential quotient of second type for different basis operators corresponding to different quantizations. Theorems and differentiation rules including differentiation of operators with negative powers and multiple differentiation were also investigated. We show that the Hamiltonian obtained from Weyl, simplest symmetric, and Born-Jordan quantization all satisfy the required algebra of the quantum equations of motion.

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Roland C. Farrell

Sat Sep 07 2024 12:00:00 (1 week)

# 27.

arXiv:2409.03123v1 Announce Type: new Abstract: The separation between physics at low and high energies is essential for physics to have any utility; the details of quantum gravity are not necessary to calculate the trajectory of a cannon ball. However, physics at low and high energies are not completely independent, and this thesis explores two ways that they are related. The first is through a UV/IR symmetry that relates scattering processes at low and high energies. This UV/IR symmetry manifests in geometrical properties of the $S$-matrix, and of the RG flow of the coupling constants in the corresponding effective field theory. Low energy nuclear physics nearly realizes this UV/IR symmetry, providing an explanation for the smallness of shape parameters in the effective range expansion of nucleon-nucleon scattering, and inspiring a new way to organize the interactions between neutrons and protons. The second is through the use of quantum computers to simulate lattice gauge theories. Quantum simulations rely on the universality of the rules of quantum mechanics, which can be applied equally well to describe a (low energy) transmon qubit at 15 milli-Kelvin as a (high energy) 1 TeV quark. This thesis presents the first simulations of one dimensional lattice quantum chromodynamics on a quantum computer, culminating in a real-time simulation of beta-decay. Results from the first simulations of a lattice gauge theory on 100+ qubits of a quantum computer are also presented. The methods developed in this thesis for quantum simulation are “physics-aware”, and are guided by the symmetries and hierarchies in length scales of the systems being studied. Without these physics-aware methods, 100+ qubit simulations of lattice gauge theories would not have been possible on the noisy quantum computers that are presently available.

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Miguel Gallego, Borivoje Daki\’c

Sat Sep 07 2024 12:00:00 (1 week)

# 28.

arXiv:2409.03001v1 Announce Type: new Abstract: The quantum description of the microscopic world is incompatible with the classical description of the macroscopic world, both mathematically and conceptually. Nevertheless, it is generally accepted that classical mechanics emerges from quantum mechanics in the macroscopic limit. In this letter, we challenge this perspective and demonstrate that the behavior of a macroscopic system can retain all aspects of the quantum formalism, in a way that is robust against decoherence, particle losses and coarse-grained (imprecise) measurements. This departure from the expected classical description of macroscopic systems is not merely mathematical but also conceptual, as we show by the explicit violation of a Bell inequality and a Leggett-Garg inequality.

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Yuxi Liu

Sat Sep 07 2024 12:00:00 (1 week)

# 29.

arXiv:2409.02962v1 Announce Type: new Abstract: We present a geometrical way of understanding the dynamics of wavefunctions in a free space, using the phase-space formulation of quantum mechanics. By visualizing the Wigner function, the spreading, shearing, the so-called “negative probability flow” of wavefunctions, and the long-time asymptotic dispersion, are intuited visually. These results are not new, but previous derivations were analytical, whereas this paper presents elementary geometric arguments that are almost “proofs without words”, and suitable for a first course in quantum mechanics.

Derivation of a Schrödinger Equation for Single Neurons Through Stochastic Neural Dynamics

Despite the prevalent view that quantum mechanics is irrelevant to macroscopic biological systems because of inherent noise and decoherence, this paper demonstrates that the electrical noise (Brownian motion) in neuron membranes gives rise to an `emergent’ Schrödinger equation involving a new neuronal constant ℏ^, fundamentally challenging the standard view of neuronal behaviour. This result could provide new insights into the underlying mechanisms of brain function, thus challenging existing paradigms in both quantum physics and neuroscience. A possible empirical test of this emergent quantum behaviour would be to look for quantum fluctuations in subthreshold neural oscillations.

arXiv:2406.16991 [q-bio.NC]