Vacuum polarization around cosmic strings in de Sitter spacetime

TL;DR

This paper investigates how cosmic strings in de Sitter spacetime affect the polarization and energy flux of quantum vacuum states for various fields, revealing curvature-dependent effects and new flux phenomena.

Contribution

It provides a detailed analysis of vacuum polarization effects around cosmic strings in de Sitter space, highlighting the role of spacetime curvature and introducing the concept of vacuum energy flux.

Findings

Vacuum polarization depends on the distance from the string and the spacetime curvature.

A new vacuum energy flux appears in the radial direction around the string.

Curvature effects are significant at distances comparable to the de Sitter radius.

Abstract

Cosmic strings are the most popular topological defects arising from the spontaneous breaking of fundamental symmetries in the early Universe. They are the source of a number of interesting effects in cosmology and astrophysics. An interesting effect is the polarization of the vacuum state for quantum fields induced by the non-trivial topology of the spacetime around cosmic strings. In the present paper we describe the combined effects of the straight cosmic string and the gravitational field on the local properties of scalar, spinor and electromagnetic vacua. The local de Sitter spacetime is considered as the background geometry. It is shown that the influence of the spacetime curvature is essential at distances from the string of the order of or larger than the curvature radius. A qualitatively new feature is the appearance of the vacuum energy flux in the radial direction with respect to the cosmic string.