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We consider classical particles coupled to the quantized electromagnetic field in the background of a spatially flat Robertson-Walker universe. We find that these particles typically undergo Brownian motion and acquire a non-zero mean…

General Relativity and Quantum Cosmology · Physics 2011-07-19 Carlos H. G. Bessa , Valdir B. Bezerra , L. H. Ford

We study the creation of massless scalar particles from the quantum vacuum due to the dynamical Casimir effect by spherical shell with oscillating radius. In the case of a small amplitude of the oscillation, to solve the infinite set of…

High Energy Physics - Theory · Physics 2011-07-19 M. R. Setare , A. A. Saharian

The spectrum of created particles during the tunneling process, leading to the decay of a false vacuum state, is studied numerically in the thick-wall approximation. It is shown that in this case the particle production is very intensive…

High Energy Physics - Theory · Physics 2009-11-10 Michael Maziashvili

We investigate a cosmological scenario in which the dark matter particles can be created during the evolution of the Universe. By regarding the Universe as an open thermodynamic system and using non-equilibrium thermodynamics, we examine…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-20 Z. Safari , K. Rezazadeh , B. Malekolkalami

We study collisions of many point-like particles in three-dimensional anti-de Sitter space, generalizing the known result with two particles. We show how to construct exact solutions corresponding to the formation of either a black hole or…

General Relativity and Quantum Cosmology · Physics 2016-11-24 E. J. Lindgren

We study particle production aspect in the flat FRW universe in the framework of $f(T)$ gravity. The matter is minimally coupled with the gravity and an exact power-law solution is obtained by solving the Friedmann equations, and matter is…

General Physics · Physics 2013-03-26 M. R. Setare , M. J. S. Houndjo

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 compute the particle creation of a harmonic oscillator using the classical stochastic method. This recently constructed method reproduces all the vacuum expectation values in quantum theory. We prepare the vacuum state at the initial…

High Energy Physics - Theory · Physics 2025-03-11 Takayuki Hirayama

Motivated by the possibility to use Bose-Einstein condensates as quantum simulators for spacetime curvature, we study a massless relativistic scalar quantum field in spatially curved Friedmann-Lema\^itre-Robertson-Walker universes with…

General Relativity and Quantum Cosmology · Physics 2022-06-22 Natalia Sánchez-Kuntz , Álvaro Parra-López , Mireia Tolosa-Simeón , Tobias Haas , Stefan Floerchinger

In this thesis, we investigate the dynamical Casimir effect, the creation of particles from vacuum by dynamical boundary conditions or dynamical background, and its backreaction to the motion of the boundary. The backreaction of particle…

High Energy Physics - Theory · Physics 2024-05-17 Yu-Cun Xie

In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is…

General Relativity and Quantum Cosmology · Physics 2016-05-17 Subenoy Chakraborty , Supriya Pan , Subhajit Saha

We use the language of squeezed states to give a systematic description of two issues in cosmological particle creation: a) Dependence of particle creation on the initial state specified. We consider in particular the number state, the…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Be-lok Hu , G. Kang , Andrew Matacz

We study particle production in infrared-modified gravitational theories in the contemporary universe. It is shown that in astronomical systems with rising mass density, the curvature scalar may oscillate with very high frequency. These…

General Relativity and Quantum Cosmology · Physics 2015-06-16 E. V. Arbuzova , A. D. Dolgov , L. Reverberi

We use the Bogoliubov formalism to study both, particles and gravitons creation at the reheating epoch, after a phase transition from inflation to a radiation dominated universe. The modes of the inflaton field fluctuations and the scalar…

General Relativity and Quantum Cosmology · Physics 2011-10-07 Mariano Anabitarte , Mauricio Bellini

Kerr's multi-particle solution is obtained on the base of the Kerr theorem. Choosing generating function of the Kerr theorem $F$ as a product of partial functions $F_i$ for spinning particles i=1,...k, we obtain a multi-sheeted,…

High Energy Physics - Theory · Physics 2008-11-26 Alexander Burinskii

If our Universe is a 3+1 brane in a warped 4+1 dimensional bulk so that its expansion can be understood as the motion of the brane in the bulk, the time dependence of the boundary conditions for arbitrary bulk fields can lead to particle…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-22 Ruth Durrer , Marcus Ruser , Marc Vonlanthen , Peter Wittwer

Among the different methods to derive particle creation, finding the quantum stress tensor expectation value gives a covariant quantity which can be used for examining the back-reaction issue. However this tensor also includes vacuum…

General Relativity and Quantum Cosmology · Physics 2015-06-03 Javad T. Firouzjaee , George F. R. Ellis

In this paper we have given a generalisation of the earlier work by Prigogine et al. who have constructed a phenomenological model of entropy production via particle creation in the very early universe generated out of the vacuum rather…

General Relativity and Quantum Cosmology · Physics 2015-06-05 G. K. Goswami , Mandwi Trivedi

Modified gravity theories with a nonminimal coupling between curvature and matter offer a compelling alternative to dark energy and dark matter by introducing an explicit interaction between matter and curvature invariants. Two of the main…

General Relativity and Quantum Cosmology · Physics 2025-10-29 Francisco S. N. Lobo , Tiberiu Harko , Miguel A. S. Pinto

We calculate the average numbers of closed, flat, and open universes spontaneously created from nothing in third quantization. The creation of universes is exponentially suppressed for large values of the kinetic energy of the inflaton,…

General Relativity and Quantum Cosmology · Physics 2020-08-19 Leonardo Campanelli
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