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physics.hist-ph updates on arXiv.org
by
Freeman J. Dyson
Fri May 19 2023 09:37:27 (1 day)
# 1.
A gravitational machine is defined as an arrangement of gravitating masses from which useful energy can be extracted. It is shown that such machines may exist if the masses are of normal astronomical size. A simple example of a gravitational machine, consisting of a double star with smaller masses orbiting around it, is described. It is shown that an efficient gravitational machine will also be an emitter of gravitational radiation. The emitted radiation sets a limit on the possible performance of gravitational machines, and also provides us with a possible means for detecting such machines if they exist.
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physics.hist-ph updates on arXiv.org
by
Galina Weinstein
Fri May 19 2023 09:37:26 (1 day)
# 2.
There has been a great buzz surrounding Daniel Jafferis et al.’s latest Nature paper, “Traversable wormhole dynamics on a quantum processor”. The Nature paper discusses an experiment in which Google’s Sycamore quantum processor is used to simulate a sparse N = 7 SYK model with 5 terms (a learned Hamiltonian). The Nature paper shows that the learned Hamiltonian preserves the key gravitational characteristics of an N = 10 SYK model with 210 terms and is sufficient to produce a traversable wormhole behavior. I will examine the experiment and discuss some philosophical challenges concerning the experiment in memory of Ian Hacking. Recently, Norman Yao and two graduate students discovered multiple flaws in Jafferis et al.’s learned Hamiltonian and uploaded a comment on the Nature paper. As expected, Jafferis and his team found a simple way to clarify the misunderstanding. They found a physical justification that allowed them to avoid the problem. In this paper, I elucidate the main arguments Yao and his students raised and the way Jafferis et al. found to save their learned Hamiltonian. I will end this paper with a philosophical comment on this recent development in the context of the learned Hamiltonian.
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by
Miguel Murça, Duarte Magano, Yasser Omar
Fri May 19 2023 09:37:23 (1 day)
# 3.
Despite the promise that fault-tolerant quantum computers can efficiently solve classically intractable problems, it remains a major challenge to find quantum algorithms that may reach computational advantage in the present era of noisy, small-scale quantum hardware. Thus, there is substantial ongoing effort to create new quantum algorithms (or adapt existing ones) to accommodate depth and space restrictions. By adopting a hybrid query perspective, we identify and characterize two methods of “breaking down” quantum algorithms into rounds of lower (query) depth, designating these approaches as “parallelization” and “interpolation”. To the best of our knowledge, these had not been explicitly identified and compared side-by-side, although one can find instances of them in the literature. We apply them to two problems with known quantum speedup: calculating the $k$-threshold function and computing a NAND tree. We show that for the first problem parallelization offers the best performance, while for the second interpolation is the better choice. This illustrates that no approach is strictly better than the other, and so that there is more than one good way to break down a quantum algorithm into a hybrid quantum-classical algorithm.
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by
Edgar Shaghoulian
Fri May 19 2023 09:37:15 (1 day)
# 4.
The measurement problem in quantum mechanics is almost exclusively discussed in situations where gravity is ignored. We discuss some recent developments in our understanding of quantum gravity and argue that they significantly alter the problem. Quantum gravity may even resolve one of the thorniest questions in discussions of the measurement problem: who collapses the wavefunction of the entire universe?
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PhilSci-Archive: No conditions. Results ordered -Date Deposited.
Fri May 19 2023 03:10:14 (1 day)
# 5.
Iranzo-Ribera, Noelia (2017) The Status of Bohr’s Complementarity Today: A study of the nature of knowing and being. UNSPECIFIED.
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Thu May 18 2023 01:51:22 (2 days)
# 6.
Earman, John S (2023) As Revealing in the Breach as in the Observance: von Neumann’s Uniqueness Theorem. [Preprint]
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physics.hist-ph updates on arXiv.org
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Enrique M. Padilla, Birgit L. Emberger, Manuel Diez-Minguito
Wed May 17 2023 09:19:00 (3 days)
# 7.
In 1926 Albert Einstein gave a clear explanation of the physical processes involved in the meander formation and evolution in open channels (Einstein, 1926). Although this work is far from being recognized as one of his greatest achievements, such as his annus mirabilis papers in 1905, he shows a truly remarkable didactic skills that make it easy to understand even to the non-specialist. In particular, a brilliant explanation of the tea leaf paradox can be found in this paper of 1926, presented as a simple experiment for clarifying the role of Earth rotation and flow curvature in the differential river banks erosion. This work deserves to be considered as a pioneering work that has laid a basic knowledge in currently very active research fields in fluvial geomorphology, estuarine physics, and hydraulic engineering. In response to the curiosity aroused and transmitted to the authors over the years by undergraduates and MSc. students, and also due to its historical and scientific significance, we present here the Spanish translation of Einstein’s original work published in German in 1926 in Die Naturwissenschaften (Einstein, 1926). Einstein’s drawings have not been interpreted, but just updated preserving their original spirit.
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Wed May 17 2023 00:57:27 (3 days)
# 8.
Fletcher, Samuel C. and Weatherall, James Owen (2022) The Local Validity of Special Relativity, Part 2: Matter Dynamics. [Preprint]
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Wed May 17 2023 00:56:44 (3 days)
# 9.
Fletcher, Samuel C. and Weatherall, James Owen (2022) The Local Validity of Special Relativity, Part 1: Geometry. [Preprint]
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Wed May 17 2023 00:55:09 (3 days)
# 10.
Jaksland, Rasmus (2023) Decoherence, appearance, and reality in agential realism. European Journal for Philosophy of Science. ISSN 1879-4912
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Wed May 17 2023 00:54:10 (3 days)
# 11.
Asenjo, Felipe and Hojman, Sergio and Linnemann, Niels and Read, James (2023) Abnormal light signals and the underdetermination of theory by evidence in astrophysics. [Preprint]
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Wed May 17 2023 00:53:04 (3 days)
# 12.
Tasdan, Ufuk I and Thebault, Karim P Y (2023) Spacetime Conventionalism Revisited. [Preprint]
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Tue May 16 2023 01:00:40 (4 days)
# 13.
Linnemann, Niels and Read, James and Teh, Nicholas (2023) The local validity of special relativity from an EFT-inspired perspective. [Preprint]
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Tue May 16 2023 00:58:10 (4 days)
# 14.
Bacciagaluppi, Guido (2023) A Proof of Specker’s Principle. [Preprint]
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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.
by
Thorsten Emig and Giuseppe Bimonte
Mon May 15 2023 18:00:00 (4 days)
# 15.
Author(s): Thorsten Emig and Giuseppe Bimonte
Recent measurements of Casimir forces have provided evidence of an intricate modification of quantum fluctuations of the electromagnetic field in complex geometries. Here we introduce a multiple scattering description for Casimir interactions between bodies of arbitrary shape and material compositio…
[Phys. Rev. Lett. 130, 200401] Published Mon May 15, 2023
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PRL: General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.
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Joseph Broz, Bingran You, Sumanta Khan, Hartmut Häffner, David E. Kaplan, and Surjeet Rajendran
Mon May 15 2023 18:00:00 (4 days)
# 16.
Author(s): Joseph Broz, Bingran You, Sumanta Khan, Hartmut Häffner, David E. Kaplan, and Surjeet Rajendran
Quantum mechanics requires the time evolution of the wave function to be linear. While this feature has been associated with the preservation of causality, a consistent causal nonlinear theory was recently developed. Interestingly, this theory is unavoidably sensitive to the full physical spread of …
[Phys. Rev. Lett. 130, 200201] Published Mon May 15, 2023
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physics.hist-ph updates on arXiv.org
by
Erik Aurell, Ryoichi Kawai
Mon May 15 2023 13:35:41 (4 days)
# 17.
G\”oran Lindblad in 1983 published a monograph on non-equilibrium thermodynamics. We here summarize the contents of this book, and provide a perspective on its relation to later developments in statistical physics and quantum physics. We high-light two aspects. The first is the idea that while all unitaries can be allowed in principle, different theories result from limiting which unitary evolutions are realized in the real world. The second is that Lindblad’s proposal for thermodynamic entropy (as opposed to information-theoretic entropy) foreshadows much more recent investigations into optimal quantum transport which is a current research focus in several fields.
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physics.hist-ph updates on arXiv.org
by
Claus Kiefer
Mon May 15 2023 13:35:40 (4 days)
# 18.
I investigate the question whether G\”odel’s undecidability theorems play a crucial role in the search for a unified theory of physics. I conclude that unless the structure of space-time is fundamentally discrete we can never decide whether a given theory is the final one or not. This is relevant for both canonical quantum gravity and string theory.
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by
Stefanie Reichert
Mon May 15 2023 08:00:00 (5 days)
# 19.
Nature Physics, Published online: 15 May 2023; doi:10.1038/s41567-023-02047-x
Measured expectations
