Dynamics of scalar fields in an expanding/contracting cosmos at finite temperature

Abstract

This paper extends the study of the quantum dissipative effects of a cosmological scalar field by taking into account the cosmic expansion and contraction. Cheung, Drewes, Kang and Kim calculated the effective action and quantum dissipative effects of a cosmological scalar field. The analytic expressions for the effective potential and damping coefficient were presented using a simple scalar model with quartic interaction. Their work was done using Minkowski-space propagators in loop diagrams. In this work we incorporate the Hubble expansion and contraction of the comic background, and focus on the thermal dynamics of a scalar field in a regime where the effective potential changes slowly. We let the Hubble parameter, $H$, attain a small but non-zero value and carry out calculations to first order in $H$. If we set $H=0$ all results match those obtained previously in flat spacetime [1]. Interestingly we have to integrate over the resonances, which in turn leads to an amplification of the effects of a non-zero $H$. This is an intriguing phenomenon which cannot be uncovered in flat spacetime. The implications on particle creations in the early universe will be studied in a forthcoming work.

arXiv comment31 pages; 4 appendices. An appendix is added in Version 2 to calculate the free spectral function of a scalar field in de Sitter space, to justify the replacements proposed in (2.3)&(2.4) in order to rewrite the propagators obtained by Drewes, Mendizabal and Weniger in terms of cosmic time

References in corpus (33)

• Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC
• Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC
• Dynamics of dark energy
• Cosmology and the Fate of Dilatation Symmetry
• A Dynamical Solution to the Problem of a Small Cosmological Constant and Late-time Cosmic Acceleration
• Reheating after Inflation
• The Ekpyrotic Universe: Colliding Branes and the Origin of the Hot Big Bang
• Gauge Singlet Scalars as Cold Dark Matter
• The Minimal Model of Nonbaryonic Dark Matter: A Singlet Scalar
• Universe Reheating after Inflation
• Microlocal Analysis and Interacting Quantum Field Theories: Renormalization on Physical Backgrounds
• Bouncing Cosmologies: Progress and Problems
• A Critical Review of Classical Bouncing Cosmologies
• Electroweak Baryogenesis and the Expansion Rate of the Universe
• Self-interacting Dark Matter and Invisibly Decaying Higgs
• Cosmological perturbations through a simple bounce
• Turning Around the Sphaleron Bound: Electroweak Baryogenesis in an Alternative Post-inflationary Cosmology
• Two Field Matter Bounce Cosmology
• A Matter Bounce By Means of Ghost Condensation
• The Matter Bounce Curvaton Scenario
• Nonequilibrium Dynamics of Scalar Fields in a Thermal Bath
• CMB constraints on the inflaton couplings and reheating temperature in $\alpha$-attractor inflation
• Dynamical System Analysis for Inflation with Dissipation
• Fate of oscillating scalar fields in the thermal bath and their cosmological implications
• Dynamics of Interacting Scalar Fields in Expanding Space-Time
• The Boltzmann Equation from Quantum Field Theory
• Particle production and reheating in the inflationary universe
• What can the CMB tell about the microphysics of cosmic reheating?
• Mass Density Perturbations from Inflation with Thermal Dissipation
• A Classical-Quantum Correspondence and Backreaction
• Fluctuation-dissipation dynamics of cosmological scalar fields
• Effective Action for Cosmological Scalar Fields at Finite Temperature
• Bouncing universe and non-BPS branes

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• The Thermal Feedback Effects on the Temperature Evolution during Reheating