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The quanta of phantom dark energy models are negative energy particles, whose maximum magnitude of energy $|E|$ must be less than a cutoff $\Lambda\lesssim 20\,$MeV. They are produced by spontaneous decay of the vacuum into phantoms plus…

High Energy Physics - Phenomenology · Physics 2024-01-11 James M. Cline

The basic thermodynamic quantities for a non-interacting scalar field in a periodic potential composed of either a one-dimensional chain of Dirac $\delta$-$\delta^\prime$ functions or a specific potential with extended compact support are…

Mathematical Physics · Physics 2020-04-22 M. Bordag , J. M. Muñoz-Castañeda , L. Santamaría-Sanz

In this paper it is shown that the quantum state of a multiverse made up of classically disconnected regions of the space-time, whose dynamical evolution is dominated by a homogeneous and isotropic fluid, is given by a squeezed state. These…

General Relativity and Quantum Cosmology · Physics 2012-07-27 Salvador Robles-Perez , Pedro F. Gonzalez-Diaz

We revise the conditions for the physical viability of a cosmological model in which dark matter has bulk viscosity and also interacts with dark energy. We have also included radiation and baryonic matter components; all matter components…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Arturo Avelino , Yoelsy Leyva , L. Arturo Urena-Lopez

We present a consistent thermodynamic theory for the resonant level model in the wide band limit, whose level energy is driven slowly by an external force. The problem of defining 'system' and 'bath' in the strong coupling regime is…

Mesoscale and Nanoscale Physics · Physics 2017-05-05 Anton Bruch , Mark Thomas , Silvia Viola Kusminskiy , Felix von Oppen , Abraham Nitzan

We aim at the construction of dark energy models without exotic matter but with a phantom-like equation of state (an effective phantom phase). The first model we consider is decaying vacuum cosmology where the fluctuations of the vacuum are…

High Energy Physics - Theory · Physics 2009-09-17 Emilio Elizalde , Shin'ichi Nojiri , Sergei D. Odintsov , Peng Wang

The presented paper is an attempt to investigate the dynamical states of an hydrodynamical isothermal turbulent self-gravitating system using some powerful tools of the classical thermodynamics. Our main assumption, inspired by the work of…

Astrophysics of Galaxies · Physics 2023-11-21 Sava Donkov , Ivan Zh. Stefanov , Todor V. Veltchev

In this paper we investigate the power spectrum of thermal fluctuations in very early stage of viscous cosmology. When the state parameter as well as the viscous coefficient of a barotropic fluid is properly chosen, a scale invariant…

General Relativity and Quantum Cosmology · Physics 2010-03-30 Wei-Jia Li , Yi Ling , Jian-Pin Wu , Xiao-Mei Kuang

The results of the paper of Verlinde [hep-th/0008140], discussing the holographic principle in a radiation dominated universe, are extended when allowing the cosmic fluid to possess a bulk viscosity. This corresponds to a non-conformally…

General Relativity and Quantum Cosmology · Physics 2009-01-14 I. Brevik , S. D. Odintsov

A general thermodynamic treatment of dissipative relativistic fluids is introduced, where the temperature four vector is not parallel to the velocity field of the fluid. Generic stability and kinetic equilibrium points out a particular…

General Relativity and Quantum Cosmology · Physics 2014-05-27 P. Ván , T. S. Biró

We show how the macroscopic state variables pressure, entropy and temperature of equilibrium thermodynamics can be consistently derived from the (quantum) chaotic spectral structure of one or two particles in two-dimensional domains. This…

The consideration of dark energy's quanta, required also by thermodynamics, introduces its chemical potential into the cosmological equations. Isolating its main contribution, we obtain solutions with dark energy decaying to matter or…

Astrophysics · Physics 2008-11-26 J. Besprosvany

We study particle creation in the presence of bulk viscosity of cosmic fluid in the early universe within the framework of open thermodynamical systems. Since the first-order theory of non-equilibrium thermodynamics is non-causal and…

General Relativity and Quantum Cosmology · Physics 2015-04-30 Mehdi Eshaghi , Nematollah Riazi , Ahmad Kiasatpour

We focus on the thermodynamic behavior of Polytropic gas as a candidate for dark energy. We use the general arguments of thermodynamics to investigate its properties and behavior. We find that a Polytropic gas may exhibit the dark energy…

General Physics · Physics 2015-10-12 H. Moradpour , A. Abri , H. Ebadi

We study a cosmological model composed of a dark energy fluid interacting with a viscous matter fluid in a spatially flat Universe. The matter component represents the baryon and dark matter and it is taken into account, through a bulk…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Arturo Avelino

In this paper, we investigate the phenomenon of particle rebound in a viscous incompressible fluid environment. We focus on the important case of no-slip boundary conditions, for which it is by now classical that, under certain assumptions,…

Analysis of PDEs · Mathematics 2020-11-04 Giovanni Gravina , Sebastian Schwarzacher , Ondřej Souček , Karel Tůma

We investigate the interaction between dark energy and dark matter in the framework of irreversible thermodynamics of open systems with matter creation/annihilation. We consider dark energy and dark matter as an interacting two component…

General Relativity and Quantum Cosmology · Physics 2013-02-08 Tiberiu Harko , Francisco S. N. Lobo

In this paper we have investigated the general form of viscous and non-viscous dark energy equation of state (EoS) parameter in the scope of anisotropic Bianchi type I space-time. We show that the presence of bulk viscosity causes…

General Relativity and Quantum Cosmology · Physics 2014-03-20 Hassan Amirhashchi , Anirudh Pradhan

In this paper, a statistical physical derivation of thermodynamically consistent fluid mechanical equations is presented for non-isothermal viscous molecular fluids. The coarse-graining process is based on (i) the adiabatic expansion of the…

Statistical Mechanics · Physics 2024-04-18 Gyula I. Tóth

We discuss the generic phase diagrams of pure systems that remain fluid near zero temperature. We call this phase a quantum fluid. We argue that the signature of the transition is the change of sign of the chemical potential, being negative…

Quantum Gases · Physics 2011-09-09 Victor Romero-Rochin