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We study adiabatic (curvature) and entropy (isocurvature) perturbations produced during a period of cosmological inflation that is driven by multiple scalar fields with an arbitrary interaction potential. A local rotation in field space is…

Astrophysics · Physics 2009-10-31 Christopher Gordon , David Wands , Bruce A. Bassett , Roy Maartens

High dissipative regime of warm pseudoscalar inflation model \cite{Kamali:2019ppi} with an approximately constant value of dissipation parameter $Q$ is studied. { Intermediate solution of the scale-factor related to the accelerated…

General Relativity and Quantum Cosmology · Physics 2021-11-23 Vahid Kamali , Saeid Ebrahimi , Asma Alaei

We discuss the spectrum of scalar density perturbations from warm inflation when the friction coefficient $\Gamma$ in the inflaton equation is dependent on the inflaton field. The spectral index of scalar fluctuations depends on a new…

Astrophysics · Physics 2009-11-10 Lisa M. H. Hall , Ian G. Moss , Arjun Berera

We develop a covariant method for studying the effects of a reheating phase on the primordial adiabatic and isocurvature perturbations in two-field models of inflation. To model the decay of the scalar fields into radiation at the end of…

High Energy Physics - Theory · Physics 2018-12-12 Pablo González , Gonzalo A. Palma , Nelson Videla

The thermalization of an isolated quantum system is described by quantum mechanics and thermodynamics, while these two subjects are still not fully consistent with each other. This leaves a less-explored region where both quantum and…

Quantum Gases · Physics 2024-11-22 Yuqing Wang , Libo Liang , Qinpei Zheng , Qi Huang , Wenlan Chen , Jing Zhang , Xuzong Chen , Jiazhong Hu

The article represents a research of the cosmological evolution of fermion statistical systems with fantom scalar interaction where "kinetic" term's contribution to the total energy of a scalar field is negative. As a result of analytical…

General Relativity and Quantum Cosmology · Physics 2016-08-18 Yurii Ignat'ev , Alexander Agathonov , Dmitry Ignatyev

Formulas are derived for the coupled quadrupolar and monopolar oscillations of a fermion condensate trapped in a axially symmetric harmonic potential. We consider two-component condensates with a large particle-particle scattering length…

Atomic Physics · Physics 2007-05-23 G. F. Bertsch , A. Bulgac , R. A. Broglia

Warm inflation model with bulk viscous pressure in the context of "intermediate inflation" where the cosmological scale factor expands as $a(t)=a_0\exp(At^f)$, is studied. The characteristics of this model in slow-roll approximation and in…

General Relativity and Quantum Cosmology · Physics 2015-06-18 M. R. Setare , V. Kamali

The interaction among the components of a hybrid quantum system is often neglected when considering the coupling of these components to an environment. However, if the interaction strength is large, this approximation leads to unphysical…

We show that dissipative effects have a significant impact on the evolution of cosmological scalar fields, leading to friction, entropy production and field fluctuations. We explicitly compute the dissipation coefficient for different…

High Energy Physics - Phenomenology · Physics 2015-05-06 Sam Bartrum , Arjun Berera , Joao G. Rosa

The two approaches to compute perturbations in warm inflation are examined. It is shown that both approaches lead to different expressions for the amplitude of the primordial spectrum, with a difference between them of $\Upsilon/(4H)$ at…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-30 Mar Bastero-Gil , Arjun Berera , Jaime R. Calderón

Warm inflation, its different particle physics model implementations and the implications of dissipative particle production for its cosmology are reviewed. First, we briefly present the background dynamics of warm inflation and contrast it…

High Energy Physics - Phenomenology · Physics 2023-03-01 Vahid Kamali , Meysam Motaharfar , Rudnei O. Ramos

Hamilton-Jacobi formalism as a powerful method is being utilized to reconsider warm inflationary scenario, where the scalar field as the main component deriving inflation interacts with other field. Separating the context to strong and weak…

General Relativity and Quantum Cosmology · Physics 2017-08-08 K. Sayar , A. Mohammadi , L. Akhtari , Kh. Saaidi

We consider the non-equilibrium evolution of the inflaton field coupled to both lighter scalars and fermions. The dissipational dynamics of this field is studied and found to be quite different than that believed in inflationary models. In…

High Energy Physics - Phenomenology · Physics 2009-09-25 D. Boyanovsky , M. D'Attanasio , H. J. de Vega , R. Holman , D. S. -Lee , A. Singh

We investigate the phenomenology of warm inflation and present generic results about the evolution of the inflaton and radiation fields. The general conditions required for warm inflation to take place are derived and discussed. A…

Astrophysics · Physics 2009-10-31 A. N. Taylor , A. Berera

We present a detailed and systematic analysis of the coarse-grained, nonequilibrium dynamics of a scalar inflaton field coupled to a fermion field in the latter stages of the reheating period of inflationary cosmology. We derive coupled…

High Energy Physics - Phenomenology · Physics 2009-10-30 S. A. Ramsey , B. L. Hu , A. M. Stylianopoulos

The many-body physics at quantum phase transitions shows a subtle interplay between quantum and thermal fluctuations, emerging in the low-temperature limit. In this review, we first give a pedagogical introduction to the equilibrium…

Statistical Mechanics · Physics 2026-04-22 Davide Rossini , Ettore Vicari

We consider one-loop thermal effects on the decay of a scalar field zero mode initially dominating the energy density of the universe. We assume fermionic decay channels and take into account the effects due to both particle and hole…

High Energy Physics - Phenomenology · Physics 2009-11-10 K. Enqvist , J. Hogdahl

We study aging dynamics in two non-disordered spin models with multi-spin interactions, following a sudden quench to low temperature. The models are relevant to the physics of supercooled liquids. Their low temperature dynamics resemble…

Statistical Mechanics · Physics 2009-11-11 Robert L. Jack , Ludovic Berthier , Juan P. Garrahan

The phase transition patterns displayed by a model of two coupled complex scalar fields are studied at finite temperature and chemical potential. Possible phenomena like symmetry persistence and inverse symmetry breaking at high…

High Energy Physics - Phenomenology · Physics 2023-02-24 Manuella C. Silva , Rudnei O. Ramos , Ricardo L. S. Farias