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Free keywords:
High Energy Physics - Theory, hep-th, Condensed Matter, Statistical Mechanics, cond-mat.stat-mech,General Relativity and Quantum Cosmology, gr-qc,High Energy Physics - Phenomenology, hep-ph,Quantum Physics, quant-ph
Abstract:
In this article, we study the quantum field theoretic generalization of the
Caldeira-Leggett model in general curved space-time considering interactions
between two scalar fields in a classical gravitational background. The
thermalization phenomena is then studied from the obtained de Sitter solution
using quantum quench from one scalar field model obtained from path integrated
effective action. We consider an instantaneous quench in the time-dependent
mass protocol of the field of our interest. We find that the dynamics of the
field post-quench can be described in terms of the state of the generalized
Calabrese-Cardy (gCC) form and computed the different types of two-point
correlation functions in this context. We explicitly found the conserved
charges of $W_{\infty}$ algebra that represents the gCC state after a quench in
de Sitter space and found it to be significantly different from the flat
space-time results. We extend our study for the different two-point correlation
functions not only considering the pre-quench state as the ground state, but
also a squeezed state. We found that irrespective of the pre-quench state, the
post quench state can be written in terms of the gCC state showing that the
subsystem of our interest thermalizes in de Sitter space. Furthermore, we
provide a general expression for the two-point correlators and explicitly show
the thermalization process by considering a thermal Generalized Gibbs ensemble
(GGE). Finally, from the equal time momentum dependent counterpart of the
obtained results for the two-point correlators, we have studied the hidden
features of the power spectra and studied its consequences for different
choices of the quantum initial conditions.
