Abstract Details

Name: Karthik Rajeev
Affiliation: IUCAA, PUNE
Conference ID: ASI2020_85
Title : Generalized Schwinger effect and particle production in an expanding universe
Authors and Co-Authors : Karthik Rajeev, Sumanta Chakraborty, T. Padmanabhan
Abstract Type : Oral
Abstract Category : General Relativity and Cosmology
Abstract : We discuss several aspects of particle production in (a) time-dependent electric field and (b) expanding Friedmann background. In the first part, we provide an algebraic mapping between the differential equations describing these two phenomena. This mapping allows a direct comparison between (a) and (b) and we highlight several interesting features of both cases using this approach. We determine the form of the (equivalent) electric field corresponding to different Friedmann spacetimes and discover, for example, a time-dependent electric field which, in a specific limit, leads to a Planck's spectrum of particles. We also discuss the conditions under which the particle production in an expanding background will be non-analytic in the parameter which encodes the coupling to the curved spacetime, in close analogy with the generalized Schwinger effect. In the second part, we study the situation in which both the time-dependent electric field and an expanding background are simultaneously present. We compute the particle production rate in this context by several different methods paying special attention to its limiting forms and possible non-analytic behaviour. We also clarify several conceptual issues related to definitions of in-vacuum and out-vacuum in these systems.