Weekly Papers on Quantum Foundations (35)

Black hole singularity resolution from unitarity 

from 

gr-qc

 by 

Steffen Gielen, Luc\’ia Men\’endez-Pidal

Fri Sep 06 2024 12:00:00 (20 hours)

# 1.

arXiv:2409.03006v1 Announce Type: cross Abstract: We study the quantum dynamics of an interior planar AdS (anti-de Sitter) black hole, requiring unitarity in the natural time coordinate conjugate to the cosmological “constant of motion” appearing in unimodular gravity. Both the classical singularity and the horizon are replaced by a non-singular highly quantum region; semiclassical notions of spacetime evolution are only valid in an intermediate region. For the singularity, our results should be applicable to general black holes: unitarity in unimodular time always implies singularity resolution.

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Schwinger vs Unruh 

from 

gr-qc

 by 

G. E. Volovik

Fri Sep 06 2024 12:00:00 (20 hours)

# 2.

arXiv:2409.03316v1 Announce Type: new Abstract: It is shown that the temperatures which characterise the Unruh effect, the Gibbons-Hawking radiation from the de Sitter cosmological horizon and the Hawking radiation from the black hole horizon acquire the extra factor 2 compared with their traditional values. The reason for that is the coherence of different processes. The combination of the coherent processes also allows us to make the connection between the Schwinger pair production and the Unruh effect.

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Quantization of the Hamilton Equations of Motion 

from 

quant-ph

 by 

Ramon Jose C. Bagunu, Eric A. Galapon

Fri Sep 06 2024 12:00:00 (20 hours)

# 3.

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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High Energy Physics from Low Energy Physics 

from 

quant-ph

 by 

Roland C. Farrell

Fri Sep 06 2024 12:00:00 (20 hours)

# 4.

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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Quantum theory at the macroscopic scale 

from 

quant-ph

 by 

Miguel Gallego, Borivoje Daki\’c

Fri Sep 06 2024 12:00:00 (20 hours)

# 5.

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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Quantum wavepackets: Proofs (almost) without words 

from 

quant-ph

 by 

Yuxi Liu

Fri Sep 06 2024 12:00:00 (20 hours)

# 6.

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.

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A Natural Introduction to Fine-Tuning 

from 

physics.hist-ph

 by 

Julian De Vuyst

Fri Sep 06 2024 12:00:00 (20 hours)

# 7.

arXiv:2012.05617v2 Announce Type: replace Abstract: A well-known topic within the philosophy of physics is the problem of fine-tuning: the fact that the universal constants seem to take non-arbitrary values in order for live to thrive in our Universe. In this paper we will talk about this problem in general, giving some examples from physics. We will review some solutions like the design argument, logical probability, cosmological natural selection, etc. Moreover, we will also discuss why it’s dangerous to uphold the Principle of Naturalness as a scientific principle. After going through this paper, the reader should have a general idea what this problem exactly entails whenever it is mentioned in other sources and we recommend the reader to think critically about these concepts.

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Category-theoretic formulation of relational materialism 

from 

physics.hist-ph

 by 

Bekir Bayta\c{s}, Ozan Ekin Derin

Thu Sep 05 2024 12:00:00 (1 day)

# 8.

arXiv:2409.02487v1 Announce Type: new Abstract: This brief brochure is intended to present a philosophical theory known as relational materialism. We introduce the postulates and principles of the theory, articulating its ontological and epistemological content using the language of category theory. The identification of any existing entity is primarily characterized by its relational, finite, and non-static nature. Furthermore, we provide a categorical construction of particularities within the relational materialist onto-epistemology. Our objective is to address and transform a specific perspective prevalent in scientific communities into a productive network of philosophical commitments.

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Does Identity Have Sense? 

from 

philsci

Thu Sep 05 2024 03:07:07 (2 days)

# 9.

Rodin, Andrei (2024) Does Identity Have Sense? [Preprint]

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Spacetime Representation Theory: Setting the Scope of the ISE Method of Topological Redescription 

from 

physics.hist-ph

 by 

Daniel Grimmer

Wed Sep 04 2024 12:00:00 (2 days)

# 10.

arXiv:2306.08110v2 Announce Type: replace Abstract: Spacetime dualities arise whenever two theories — despite being structurally equivalent in some sense — seemingly provide us with two radically different spatiotemporal descriptions of the world. This often involves radical differences in how the two theories topologically stage their states; Whereas one theory is about *this* type of particle/field on *this* smooth manifold, the other theory is about *that* type of particle/field arranged differently on *that* smooth manifold. For instance, the AdS-CFT correspondence relates a certain theory set in the bulk (our 3+1 dimensional spacetime) to another theory set on the boundary (a 2+1 dimensional spacetime). Another example (new in this paper) is the M\”{o}bius-Euclid duality: a theory about a certain type of particle floating around on the Euclidean plane can be topologically redescribed as instead being about a different type of particle living on a M\”{o}bius strip, and vice versa. The possibility of such alternative spacetime framings raises some significant questions about the epistemology and metaphysics of space and time. For instance, what are our topology selection criteria? Are they objective or conventional? Moreover, given that two spacetime theories are topological redescriptions of each other, what is the common core which they are equivalent descriptions of? As a step towards answering such questions, this paper develops a general framework (spacetime representation theory) for understanding our ability to topologically redescribe our spacetime theories. With this framework established, I will then discuss the ISE Equivalence Theorem which sets the scope of the recently developed ISE Method of topological redescription.

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Classical Mechanics from Energy Conservation or: Why not Momentum? 

from 

physics.hist-ph

 by 

C. Baumgarten

Wed Sep 04 2024 12:00:00 (2 days)

# 11.

arXiv:2409.01946v1 Announce Type: cross Abstract: It is demonstrated that energy conservation allows for a “heuristic” derivation of Newtonian mechanics, if the energy is presumed to be an additive function of position and velocity. It is shown that energy must be depicted as a function of position and momentum in order to allow for the correct relativistic equations. Accordingly it is argued that not only quantum theory but also special relativity is intrinsically Hamiltonian and requires a description by coordinates and momenta instead of coordinates and velocities. Furthermore it is argued that the usual historical order of the “formulations” of mechanics, from Newtonian via Lagrangian to Hamiltonian mechanics, is illogical and misleading. Therefore it should be reversed.

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The Large-Scale Structure of Inductive Inference 

from 

philsci

Wed Sep 04 2024 01:27:18 (3 days)

# 12.

Norton, John D. (2024) The Large-Scale Structure of Inductive Inference. BSPSopen . University of Calgary Press/BSPSopen, Calgary. ISBN 978-1-77385-541-7

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Explanation, Truth and Structural Realism 

from 

philsci

Wed Sep 04 2024 01:23:43 (3 days)

# 13.

Woodward, James (2024) Explanation, Truth and Structural Realism. [Preprint]

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Quantum panprotopsychism and the structure and subject-summing combination problem 

from 

philsci

Wed Sep 04 2024 01:21:13 (3 days)

# 14.

Gambini, Rodolfo and Pullin, Jorge (0024) Quantum panprotopsychism and the structure and subject-summing combination problem. [Preprint]

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Effects of topological boundary conditions on Bell nonlocality 

from 

PRA – fundamentalconcepts

 by 

Patrick Emonts, Mengyao Hu, Albert Aloy, and Jordi Tura

Tue Sep 03 2024 18:00:00 (3 days)

# 15.

Author(s): Patrick Emonts, Mengyao Hu, Albert Aloy, and Jordi Tura

Bell nonlocality is the resource that enables device-independent quantum information processing tasks. It is revealed through the violation of so-called Bell inequalities, indicating that the observed correlations cannot be reproduced by any local hidden-variable model. While well explored in few-bo…

[Phys. Rev. A 110, 032201] Published Tue Sep 03, 2024

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What is a reference frame in General Relativity? 

from 

philsci

Sun Sep 01 2024 15:21:57 (5 days)

# 16.

Bamonti, Nicola (2024) What is a reference frame in General Relativity? [Preprint]

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Quantum panprotopsychism and the combination problem 

from 

philsci

Sat Aug 31 2024 12:21:25 (6 days)

# 17.

Gambini, Rodolfo and Pullin, Jorge (2024) Quantum panprotopsychism and the combination problem. Mind and Matter, 22 (1). pp. 51-94. ISSN 1611-8812

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