from APS selected papers by Philip BallFri Jan 26 2024 05:00:00 (1 day)# 1.
Author(s): Philip Ball
Which direction would an S-shaped lawn sprinkler rotate if it were submerged and the flow were reversed? Experiments now provide a definitive answer.
[Physics 17, 15] Published Fri Jan 26, 2024
from quant-ph by P. Gusin, D. Burys, A. RadoszThu Jan 25 2024 21:13:24 (1 day)# 2.
Combining gravity with quantum theory is still work in progress. On the one hand, classical gravity, is the geometry of space-time determined by the energy-momentum tensor of matter and the resulting nonlinear equations; on the other hand, the mathematical description of a quantum system, is Hilbert space with linear equations describing evolution. In this paper, various measures in Hilbert space will be presented. In general, distance measures in Hilbert space can be divided into measures determined by energy and measures determined by entropy. Entropy measures determine quasi-distance because they do not satisfy all the axioms defining distance. Finding a general rule to determine such a measure unambiguously seems to be fundamental.
from physics.hist-ph by Sylvio R. BistafaThu Jan 25 2024 21:13:24 (1 day)# 3.
The year 2022 marked the 200th anniversary of the first appearance of the Navier-Stokes equation, a landmark in Fluid Dynamics introduced by Claude-Louis Navier in 1822. This equation revolutionized the understanding of fluid motion by incorporating viscosity and friction into the equations, expanding their applicability beyond idealized fluids. In this manuscript, we explore the historical development of the Navier-Stokes equation and its profound impact on Fluid Dynamics over the past two centuries. From Navier’s initial insights to George Stokes’ experimental validations and subsequent contributions by other scientists, we trace the evolution of this equation. We also delve into its practical applications, including its role in the development of Computational Fluid Dynamics. The Navier-Stokes equation has played a pivotal role in advancing our understanding of fluid behavior, making it a cornerstone of modern science and engineering.
from physics.hist-ph by Tatsuaki OkamotoThu Jan 25 2024 21:13:23 (1 day)# 4.
There is a widespread assumption that the universe in general, and life in particular, is getting more complex with time. This paper formulates this assumption as a macroscopic law of increasing complexity and presents a hypothesis that this macroscopic law emerges in the universe. For this formulation, we represent any object of complexity as the source of the observed value of the object, which is a probability distribution and treated in a unified manner for various objects. To define the degree of complexity, we utilize a quantitative definition of the complexity of organized matters, organized complexity [15]. We then apply this hypothesis to the fine-tuning problem of the universe about the fundamental physical constants, which appear to be fine-tuned for life. This hypothesis explains the problem such that the fundamental physical constants are fine-tuned for the emergence of this macroscopic law, which would be more plausible and clearly defined than for life. An (approximate) reduction of this macroscopic law to fundamental physical laws would certify this law and concretely evaluate the conditions of the fundamental physical constants so that this law emerges.
from quant-ph by A. Ibort, M. Jiménez-VázquezThu Jan 25 2024 21:13:17 (1 day)# 5.
A Lagrangian description of the qubit based on a generalization of Schwinger’s picture of Quantum Mechanics using the notion of groupoids is presented. In this formalism a Feynman-like computation of its probability amplitudes is done. The Lagrangian is interpreted as a function on the groupoid describing the quantum system. Such Lagrangian determines a self-adjoint element on its associated algebra. Feynman’s paths are replaced by histories on the groupoid which form themselves a groupoid. A simple method to compute the sum over all histories is discussed. The unitarity of the propagator obtained in this way imposes quantization conditions on the Lagrangian of the theory. Some particular instances of them are discussed in detail.
from quant-ph by Bryan J DaltonThu Jan 25 2024 21:13:10 (1 day)# 6.
In this paper we consider the description by a Bell non-local hidden variable theory of bipartite quantum states with two observables per sub-system. We derive Bell inequalities of the Collins-Gisin.-Liden-Massar-Popescu type which involve combinations of the probabilities of related outcomes for measurements for the four pairs of sub-system observables. It is shown that the corresponding quantum theory expressions violate the Bell inequalities in the case of the maximally entangled state of the bipartitite system. This shows that quantum theory can not be underpinned by a non-local hidden variable theory. So as local hidden variable theory has already been shown to conflict with quantum theory, it follows that quantum theory can not be understood in terms of any hidden variable theory (which Einstein originally had expected).
from gr-qc by Ran Li, Jin WangThu Jan 25 2024 21:13:05 (1 day)# 7.
We studied the Hayden-Preskill thought experiment with the local projective measurement. Compared to the original model, the measurement is applied on the Hawking radiation that was emitted after throwing the quantum diary into the black hole. Within this setup, we explored various aspects of this model, including the information recovery from the black hole, the relation to the black hole final state proposal, the relation between the Yoshida-Kitaev protocol and Petz recovery map, the effects of the decoherence, and the quantum simulations of the decoding protocols. These aspects may provide us new insights into the non-perturbative nature of quantum black holes.
from philsciThu Jan 25 2024 02:39:22 (2 days)# 8.
Stuart, Michael T. and Sargeant, Hannah (2024) The Role of Imagination in Making Water from Moon Rocks: How Scientists Use Imagination to Break Constraints on Imagination. [Preprint]
from philsciThu Jan 25 2024 02:36:52 (2 days)# 9.
Pipa, Francisco (2023) A new indeterminacy-based quantum theory. [Preprint]
from philsciThu Jan 25 2024 02:34:41 (2 days)# 10.
Bradley, Clara and Weatherall, James Owen (2024) Conservation Principles in AQUAL. [Preprint]
from PRA – fundamentalconcepts by Ruben E. Araújo, Ricardo Ximenes, and Eduardo O. DiasWed Jan 24 2024 05:00:00 (3 days)# 11.
Author(s): Ruben E. Araújo, Ricardo Ximenes, and Eduardo O. Dias
An alternative quantization rule, in which time becomes a self-adjoint operator and position is a parameter, was proposed by Dias and Parisio [Phys. Rev. A 95, 032133 (2017)]. In this approach, the authors derived a space-time-symmetric (STS) extension of quantum mechanics (QM) where a new quantum s…
[Phys. Rev. A 109, 012221] Published Wed Jan 24, 2024
from philsciTue Jan 23 2024 17:06:36 (3 days)# 12.
Krause, Décio (2024) On Otavio Bueno on identity and quantification (v.2). [Preprint]
from philsciMon Jan 22 2024 22:57:58 (4 days)# 13.
Gao, Shan (2024) Locality Implies Reality of the Wave Function: Hardy’s Theorem Revisited. [Preprint]
from philsciMon Jan 22 2024 22:57:32 (4 days)# 14.
Henne, Céline and Tomczyk, Hannah and Sperber, Christoph (2024) Physicists’ Views on Scientific Realism. [Preprint]
from philsciMon Jan 22 2024 22:57:13 (4 days)# 15.
Jacobs, Caspar (2024) In Defence of Dimensions. [Preprint]
from philsciSat Jan 20 2024 16:35:20 (6 days)# 16.
Liu, Chong (2024) A new theory of causation based on probability distribution determinism. [Preprint]
from APS selected papers by Katherine WrightFri Jan 19 2024 05:00:00 (1 week)# 17.
Author(s): Katherine Wright
A new technique could allow researchers to distinguish the swimming motion of a species of microorganisms without the need to track individuals within a population.
[Physics 17, s8] Published Fri Jan 19, 2024
from philsciFri Jan 19 2024 03:31:16 (1 week)# 18.
Menon, Tushar (2023) Spacetime functionalists should be inferentialists. [Preprint]
from philsciThu Jan 18 2024 18:52:49 (1 week)# 19.
Woodward, James The Place of Explanation in Scientific Inquiry: Inference to the Best Explanation vs Inference to the Only Explanation. UNSPECIFIED.
