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We investigate entropy production for an expanding system of particles and resonances with isospin symmetry -- in our case pions and $\rho$ mesons -- within the framework of relativistic kinetic theory. A cascade code to simulate the…

High Energy Physics - Phenomenology · Physics 2008-11-26 Stefan Ochs , Ulrich Heinz

We explore the cosmological implications at effective level of matter creation effects in a dissipative fluid for a FLRW geometry; we also perform a statistical analysis for this kind of model. By considering an inhomogeneous Ansatz for the…

General Relativity and Quantum Cosmology · Physics 2021-01-01 Víctor H. Cárdenas , Miguel Cruz , Samuel Lepe

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

Employing the stochastic wave function method, we study quantum features of stochastic entropy production in nonequilibrium processes of open systems. It is demonstarted that continuous measurements on the environment introduce an…

Quantum Physics · Physics 2013-10-16 B. Leggio , A. Napoli , A. Messina , H. -P. Breuer

Massive scalar particle production, due to the anisotropic evolution of a five-dimensional spacetime, is considered in the context of a quadratic Lagrangian theory of gravity. Those particles, corresponding to field modes with non-vanishing…

General Relativity and Quantum Cosmology · Physics 2014-11-17 K. Kleidis , D. B. Papadopoulos

Recollapsing homogeneous and isotropic models present one of the key ingredients for cyclic scenarios. This is considered here within a quantum cosmological framework in presence of a free scalar field with, in turn, a negative cosmological…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Martin Bojowald , Reza Tavakol

This paper addresses fundamental aspects of statistical mechanics such as the motivation of a classical state space with spontaneous transitions, the meaning of non-equilibrium in the context of thermalization, and the justification of…

Statistical Mechanics · Physics 2011-05-31 Haye Hinrichsen , Christian Gogolin , Peter Janotta

We propose a general definition of nonequilibrium entropy of a classical stochastic field. As an example of particular interest in cosmology we apply this definition to compute the entropy of density perturbations in an inflationary…

Astrophysics · Physics 2009-10-22 R. Brandenberger , V. Mukhanov , T. Prokopec

The universal validity of the second law of thermodynamics is widely attributed to a finely tuned initial condition of the universe. This creates a problem: why is the universe atypical? We suggest that the problem is an artefact created by…

General Relativity and Quantum Cosmology · Physics 2015-07-27 Julian Barbour , Tim Koslowski , Flavio Mercati

We study the thermalization process in classical Yang-Mills (CYM) field theory starting from noisy glasma-like initial conditions by investigating the initial-value sensitivity of trajectories. Kunihiro et al. linked entropy generation to…

High Energy Physics - Phenomenology · Physics 2013-11-20 Hideaki Iida , Teiji Kunihiro , Berndt Mueller , Akira Ohnishi , Andreas Schaefer , Toru T. Takahashi

We consider quantum decoherence and entropy increase in early universe cosmology. We first study decoherence in a discrete bipartite quantum system for which a single qubit gets entangled with an environment and the entropy increase is…

High Energy Physics - Theory · Physics 2025-11-06 Sebastian Cespedes , Senarath de Alwis , Fernando Quevedo

The concept of entropy has been pivotal in the formulation of thermodynamics. For systems driven away from thermal equilibrium, a comparable role is played by entropy production and dissipation. Here we provide a comprehensive picture how…

Soft Condensed Matter · Physics 2025-05-15 Robin Bebon , Joshua F. Robinson , Thomas Speck

We report the study of a random Lorentz gas with a reaction of isomerization $A\rightleftharpoons B$ between the two colors of moving particles elastically bouncing on hard disks. The reaction occurs when the moving particles collide on…

Chaotic Dynamics · Physics 2009-11-10 Laszlo Matyas , Pierre Gaspard

In this work, we use the Gouy-Stodola theorem to calculate the entropy production rate in the inflationary epoch of the universe. This theorem allows us the simple calculation of entropy and entropy production rate occasioned by the…

General Relativity and Quantum Cosmology · Physics 2026-02-25 R. H. Longaresi , S. D. Campos

Chemotactic active particles, such as bacteria and cells, exhibit an adaptive run-and-tumble motion, giving rise to complex emergent behaviors in response to external chemical fields. This motion is generated by the conversion of internal…

Soft Condensed Matter · Physics 2024-02-06 Minh D. N. Nguyen , Phuc H. Pham , Khang V. Ngo , Van H. Do , Shengkai Li , Trung V. Phan

Quantum fields in cosmological spacetimes can experience particle production due to their interaction with the expanding background. This effect is particularly relevant for models of the very early Universe, when the energy density…

General Relativity and Quantum Cosmology · Physics 2019-09-04 Fernando Zago , Arthur Kosowsky

We show that the entropy of cosmological perturbations originating as quantum vacuum fluctuations in the very early universe, including the contribution of the leading nonlinear interactions, can be viewed as momentum space entanglement…

High Energy Physics - Theory · Physics 2020-11-12 Suddhasattwa Brahma , Omar Alaryani , Robert Brandenberger

Cosmological gravitational particle production (GPP) is a generic mechanism by which particles are produced during the inflationary epoch. In this work we consider the GPP of massive scalars in an effort to fully understand the spectrum of…

High Energy Physics - Phenomenology · Physics 2025-01-13 Leah Jenks , Edward W. Kolb , Keyer Thyme

It is argued that the Universe reheating in bouncing cosmologies could be explained via gravitational particle production, as due to a sudden phase transition in the contracting regime. To this end, it is shown that gravitational production…

General Relativity and Quantum Cosmology · Physics 2015-10-21 Jaume Haro , Emilio Elizalde

An accelerated universe should naturally have a vacuum energy density determined by its dynamical curvature. The cosmological constant is most likely a temporary description of a dynamical variable that has been drastically evolving from…

General Relativity and Quantum Cosmology · Physics 2015-10-28 Joan Sola
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