# Weekly Papers on Quantum Foundations (9)

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

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Eric Brunner, Lukas Pausch, Edoardo G. Carnio, Gabriel Dufour, Alberto Rodríguez, and Andreas Buchleitner

Fri Feb 24 2023 18:00:00 (16 hours)

# 1.

Author(s): Eric Brunner, Lukas Pausch, Edoardo G. Carnio, Gabriel Dufour, Alberto Rodríguez, and Andreas Buchleitner

We unveil the signature of many-body interference across dynamical regimes of the Bose-Hubbard model. Increasing the particles’ indistinguishability enhances the temporal fluctuations of few-body observables, with a dramatic amplification at the onset of quantum chaos. By resolving the exchange symm…

[Phys. Rev. Lett. 130, 080401] Published Fri Feb 24, 2023

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Fri Feb 24 2023 09:51:29 (1 day)

# 2.

Pisano, Niccolò Aimone (2023) An Instrumentalist Take on the Models of the Free-Energy Principle. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Fri Feb 24 2023 03:18:50 (1 day)

# 3.

Ruiz de Olano, Pablo (2017) Intimate Connections: Symmetries and Conservation Laws in Quantum versus Classical Mechanics. Philosophy of Science, 84 (5). pp. 1275-1288. ISSN 1539-767X

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Thu Feb 23 2023 14:48:17 (1 day)

# 4.

Christian, Joy (2023) Bell’s Theorem Begs the Question. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Thu Feb 23 2023 03:21:11 (2 days)

# 5.

Danne, Nicholas (2021) An Extra-Mathematical Program Explanation of Color Experience. [Preprint]

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Thu Feb 23 2023 03:16:49 (2 days)

# 6.

Morita, Kohei (2023) A fine-grained distinction of coarse graining. [Preprint]

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Aurélien Drezet

Wed Feb 22 2023 11:14:01 (2 days)

# 7.

The aim of this article is to discuss the preferred basis problem in relational quantum mechanics (RQM). The issue is at the heart of quantum mechanics and we first show that the mathematical formalism of RQM is immune to recent critics concerning consistency. Moreover, we also analyse the notion of interaction in RQM and provide a For All Practical Purposes (FAPP) reading of RQM comparing it with Bohmian mechanics.

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Michael Spanner

Wed Feb 22 2023 11:13:59 (2 days)

# 8.

Starting with a consideration of the implication of Bell inequalities in quantum mechanics, a new quantum postulate is suggested in order to restore classical locality and causality to quantum physics: only the relative coordinates between detected quantum events are valid observables. This postulate supports the EPR view that quantum mechanics is incomplete, while also staying compatible to the Bohr view that nothing exists beyond the quantum. The new postulate follows from a more general principle of quantum relativity, which states that only correlations between experimental detections of quantum events have a real classical existence. Quantum relativity provides a framework to differentiate the quantum and classical world.

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Wed Feb 22 2023 11:13:58 (2 days)

# 9.

It is commonly known that the steady-state model of the universe was proposed and championed in a series of influential papers around mid-twenty century by Fred Hoyle, Hermann Bondi, and Thomas Gold. In contrast it is little known that, many years before, Albert Einstein briefly explored the same idea; that is of a ‘dynamic steady state’ universe. In 1931 during his first visit to Caltech, Einstein tried to develop a model where the universe expanded and where matter was supposed to be continuously created. This latter process was proposed by him to keep the matter density of the universe constant. However, Einstein shortly abandoned the idea. The whole event has already been described and analyzed by C. O’Raifeartaigh and colleagues in 2014. It is the purpose of this brief note to point out what might have prompted Einstein to consider a continuous creation of matter and the prevailing circumstances at that time that drove Einstein’s intent.

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R. Loll, A. Silva

Wed Feb 22 2023 11:13:58 (2 days)

# 10.

There are not many tools to quantitatively monitor the emergence of classical geometric features from a quantum spacetime, whose microscopic structure may be a highly quantum-fluctuating “spacetime foam”. To improve this situation, we introduce new quantum observables that allow us to measure the absolute and relative homogeneity of geometric properties of a nonperturbative quantum universe, as function of a chosen averaging scale. This opens a new way to compare results obtained in full quantum gravity to descriptions of the early universe that assume homogeneity and isotropy at the outset. Our construction is purely geometric and does not depend on a background metric. We illustrate the viability of the quantum homogeneity measures by a nontrivial application to two-dimensional Lorentzian quantum gravity formulated in terms of a path integral over Causal Dynamical Triangulations, and find some evidence of quantum inhomogeneity.

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Scott Aaronson, Harry Buhrman, William Kretschmer

Wed Feb 22 2023 11:13:53 (2 days)

# 11.

Relational problems (those with many possible valid outputs) are different from decision problems, but it is easy to forget just how different. This paper initiates the study of FBQP/qpoly, the class of relational problems solvable in quantum polynomial-time with the help of polynomial-sized quantum advice, along with its analogues for deterministic and randomized computation (FP, FBPP) and advice (/poly, /rpoly).

Our first result is that FBQP/qpoly != FBQP/poly, unconditionally, with no oracle — a striking contrast with what we know about the analogous decision classes. The proof repurposes the separation between quantum and classical one-way communication complexities due to Bar-Yossef, Jayram, and Kerenidis. We discuss how this separation raises the prospect of near-term experiments to demonstrate “quantum information supremacy,” a form of quantum supremacy that would not depend on unproved complexity assumptions.

Our second result is that FBPP is not contained in FP/poly — that is, Adleman’s Theorem fails for relational problems — unless PSPACE is contained in NP/poly. Our proof uses IP=PSPACE and time-bounded Kolmogorov complexity. On the other hand, we show that proving FBPP not in FP/poly will be hard, as it implies a superpolynomial circuit lower bound for PromiseBPEXP.

We prove the following further results: * Unconditionally, FP != FBPP and FP/poly != FBPP/poly (even when these classes are carefully defined). * FBPP/poly = FBPP/rpoly (and likewise for FBQP). For sampling problems, by contrast, SampBPP/poly != SampBPP/rpoly (and likewise for SampBQP).

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Jian-Ming Yan, Cheng Liu, Tao Zhu, Qiang Wu, Anzhong Wang

Wed Feb 22 2023 11:13:51 (2 days)

# 12.

In this paper, we use the publicly available observational data of 17 stellar stars orbiting Sgr A* to test the quantum extension of Schwarzschild spacetime in loop quantum gravity (LQG). For our purpose, we transform the geodesical evolution of a massive particle in the quantum-extended Schwarzschild black hole to the perturbed Kepler problem and calculate the effects of LQG on the pericentre advance of the stellar stars. With these effects, one is able to compare them with the publicly available astrometric and spectroscopic data of stellar stars in the galactic center. We perform Monte Carlo Markov Chain (MCMC) simulations to probe the possible LQG effects on the orbit of S-stars. No significant evidence of the quantum-extended Schwarzschild black hole from LQG is found. Among the posterior analyses of 17 S-stars, the result of S2 gives the strongest bound on the LQG parameter $A_\lambda$, which places an upper bound at 95\% confidence level on $A_\lambda$ to be $A_\lambda < 0.302$.

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Wed Feb 22 2023 07:56:27 (3 days)

# 13.

Dewar, Neil (2023) Interpretation and equivalence; or, equivalence and interpretation. [Preprint]

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PhilSci-Archive: No conditions. Results ordered -Date Deposited.

Wed Feb 22 2023 07:54:13 (3 days)

# 14.

Galison, Peter and Doboszewski, Juliusz and Elder, Jamee and Martens, Niels C.M. and Ashtekar, Abhay and Enander, Jonas and Gueguen, Marie and Kessler, Elizabeth A. and Lalli, Roberto and Lesourd, Martin and Marcoci, Alexandru and Murgueitio Ramírez, Sebastián and Natarajan, Priyamvada and Nguyen, James and Reyes-Galindo, Luis and Ritson, Sophie and Schneider, Mike D. and Skulberg, Emilie and Sorgner, Helene and Stanley, Matthew and Thresher, Ann C. and van Dongen, Jeroen and Weatherall, James Owen and Wu, Jingyi and Wüthrich, Adrian (2023) The Next Generation Event Horizon Telescope Collaboration: History, Philosophy, and Culture. Galaxies, 11 (32).