Spectator electric fields, de Sitter spacetime, and the Schwinger effect

Massimo Giovannini

doi:10.1103/physrevd.97.061301

Abstract

During a de Sitter stage of expansion the spectator fields of different spin are constrained by the critical density bound and by further requirements determined by their specific physical nature. The evolution of spectator electric fields in conformally flat background geometries is occasionally concocted by postulating the existence of ad hoc currents but this apparently innocuous trick violates the second law of thermodynamics. Such a problem occurs, in particular, for those configurations (customarily employed for the analysis of the Schwinger effect in four-dimensional de Sitter backgrounds) leading to an electric energy density which is practically unaffected by the expansion of the underlying geometry. The obtained results are compared with more mundane situations where Joule heating develops in the early stages of a quasi-de Sitter phase.

Highlights

During a de Sitter stage of expansion, the spectator fields of different spin are constrained by the critical density bound and by further requirements determined by their specific physical nature
In the expanding de Sitter spacetime and in some of its inflationary extensions, subcritical fields induce a number of diverse physical effects that further constrain their evolution
Spectator fields appear in the analysis of the Schwinger effect in quasi-de Sitter spacetime [5]; in this context, the constancy of the energy density is achieved by considering a class of homogeneous field configurations sustained by an appropriate current

Summary

Massimo Giovannini*

The evolution of spectator electric fields in conformally flat background geometries is occasionally concocted by postulating the existence of ad hoc currents, but this apparently innocuous trick violates the second law of thermodynamics. Such a problem occurs, in particular, for those configurations (customarily employed for the analysis of the Schwinger effect in four-dimensional de Sitter backgrounds) leading to an electric energy density which is practically unaffected by the expansion of the underlying geometry.

MASSIMO GIOVANNINI

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