Effect of a positive cosmological constant on cosmic strings

TL;DR

This paper investigates how a positive cosmological constant influences cosmic strings, affecting their gravitational effects and interactions with black hole horizons in de Sitter space.

Contribution

It provides new calculations of the cosmological constant's impact on cosmic string angle deficit and geodesic bending, and demonstrates string piercing of horizons in Schwarzschild-de Sitter space.

Findings

Cosmological constant increases the angle deficit of cosmic strings.

Null geodesics are bent differently in the presence of a positive cosmological constant.

Thin cosmic strings can pierce black hole horizons in de Sitter space.

Abstract

We study cosmic Nielsen-Olesen strings in space-times with a positive cosmological constant. For the free cosmic string in a cylindrically symmetric space-time, we calculate the contribution of the cosmological constant to the angle deficit, and to the bending of null geodesics. For a cosmic string in a Schwarzschild-de Sitter space-time, we use Kruskal patches around the inner and outer horizons to show that a thin string can pierce them.