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We extend classical coarse-grained entropy, commonly used in many branches of physics, to the quantum realm. We find two coarse-grainings, one using measurements of local particle numbers and then total energy, and the second using local…

Quantum Physics · Physics 2019-01-17 Dominik Šafránek , J. M. Deutsch , Anthony Aguirre

In finite-dimensional quantum systems, temperature cannot be uniquely defined. This, in turn, implies that there are several ways to define entropy production in finite-dimensional quantum systems, because the classical entropy production…

Quantum Physics · Physics 2026-02-03 Tomohiro Nishiyama , Yoshihiko Hasegawa

Systems operating out of equilibrium exchange energy and matter with the environment, thus producing entropy in their surroundings. Since the entropy production depends on the current flowing throughout the system, its quantification is…

Statistical Mechanics · Physics 2019-12-13 Daniel Maria Busiello , Amos Maritan

We investigate an asymptotically spatially flat Robertson-Walker spacetime from two different perspectives. First, using von Neumann entropy, we evaluate the entanglement generation due to the encoded information in spacetime. Then, we work…

Quantum Physics · Physics 2017-06-21 Mehrnoosh Farahmand , Hosein Mohammadzadeh , Hossein Mehri-Dehnavi

In parametric systems, squeezed states of radiation can be generated via extra work done by external sources. This eventually increases the entropy of the system despite the fact that squeezing is reversible. We investigate the entropy…

Quantum Physics · Physics 2014-08-05 A. M. Zagoskin , E. Il'ichev , Franco Nori

After a discussion on several limiting cases where General Relativity turns into less sophisticated theories, we find that in the correct thermodynamical and cosmological weak field limit of Einstein's field equations the entropy of the…

General Physics · Physics 2010-12-14 Marcelo Samuel Berman

The theory of entropy production in nonequilibrium, Hamiltonian systems, previously described for steady states using partitions of phase space, is here extended to time dependent systems relaxing to equilibrium. We illustrate the main…

Chaotic Dynamics · Physics 2009-10-31 T. Gilbert , J. R. Dorfman , P. Gaspard

The manuscript investigates the entropy squeezing of a qubit (two-level atom) interacting with the cavity field in the Schr\"odinger cat states. The effects of the Schr\"odinger cat states of the field on the squeezing are examined. Our…

Quantum Physics · Physics 2017-10-25 Wei-Guang Wang , Xue-Qun Yan , Jiu-Ming LI

According to the second law of thermodynamics, the arrow of time points to an ever increasing entropy of the Universe. However, exactly how the entropy evolves with time and what drives the growth remain largely unknown. Here, for the first…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-09 Xinghai Zhao , Yuexing Li , Qirong Zhu , Derek Fox

Gravitational particle production has been investigated by using Einstein's gravitational field equations in the presence of a cosmological constant. To study the mechanism of particle creation, the Universe has been considered as a…

General Relativity and Quantum Cosmology · Physics 2020-04-07 Z. Safari , B. Malekolkalami , H. Moshafi

Entropy production plays a fundamental role in the study of non-equilibrium systems by offering a quantitative handle on the degree of time-reversal symmetry breaking. It depends crucially on the degree of freedom considered as well as on…

Statistical Mechanics · Physics 2022-05-04 Luca Cocconi , Guillaume Salbreux , Gunnar Pruessner

Planck-scale quantum spacetime undergoes probabilistic local curvature fluctuations whose distributions cannot explicitly depend on position otherwise vacuum's small-scale quantum structure would fail to be statistically homogeneous. Since…

High Energy Physics - Theory · Physics 2012-03-28 Christopher D. Burton

We explore the notion of generated entropy in open quantum systems. We focus on the study of the discrete-time quantum walk on the line, from the entropy production perspective. We argue that the evolution of the coin can be modeled as an…

Quantum Physics · Physics 2020-04-13 Andrés Vallejo , Alejandro Romanelli , Raúl Donangelo , Renato Portugal

Explaining how microscopic entities collectively produce macroscopic phenomena is a fundamental goal of many-body physics. Theory predicts that large-scale entanglement is responsible for exotic macroscopic phenomena, but observation of…

Entropy production is often interpreted as a proxy for microscopic disorder or environmental roughness in stochastic systems. We test this interpretation using controlled simulations of overdamped stochastic dynamics on curved surfaces in…

Statistical Mechanics · Physics 2026-02-23 Patrick Romanescu

We analyze the entropy production and the maximal extractable work from a squeezed thermal reservoir. The nonequilibrium quantum nature of the reservoir induces an entropy transfer with a coherent contribution while modifying its thermal…

Quantum Physics · Physics 2016-05-18 Gonzalo Manzano , Fernando Galve , Roberta Zambrini , Juan M. R. Parrondo

Formation of atomic pairs by the dissociation of a molecular condensate or by inelastic collisions in an atomic condensate due to a time-dependent curve crossing process is studied beyond the mean-field approximation. The number of atoms…

Condensed Matter · Physics 2009-11-07 V. A. Yurovsky , A. Ben-Reuven , P. S. Julienne

Quantum state diffusion is a framework within which measurement may be described as the continuous and gradual collapse of a quantum system to an eigenstate as a result of interaction with its environment. The irreversible nature of the…

Quantum Physics · Physics 2025-09-18 Sophia M. Walls , Adam Bloss , Ian J. Ford

The entropy produced when a system undergoes an infinitesimal quench is directly linked to the work parameter susceptibility, making it sensitive to the existence of a quantum critical point. Its singular behavior at $T=0$, however,…

Quantum Physics · Physics 2022-07-13 Adalberto D. Varizi , Raphael C. Drumond , Gabriel T. Landi

We analyze cosmology assuming unitary quantum mechanics, using a tripartite partition into system, observer and environment degrees of freedom. This generalizes the second law of thermodynamics to "The system's entropy can't decrease unless…

High Energy Physics - Theory · Physics 2013-05-30 Max Tegmark