Semiclassical gravitational effects near a singular magnetic flux

TL;DR

This paper investigates how vacuum polarization around a magnetic string influences spacetime geometry, revealing that quantum effects can cause both attractive and repulsive gravitational modifications depending on parameters.

Contribution

It provides the first semiclassical analysis of metric backreaction due to vacuum polarization of a massive charged scalar field near a magnetic string.

Findings

Gravitational potential and deficit angle can be positive or negative depending on parameters.

Quantum corrections exhibit short-range behavior unlike massless cases.

Sign of gravitational effects can change with coupling constant and magnetic flux.

Abstract

We consider the backreaction of the vacuum polarization effect for a massive charged scalar field in the presence of a singular magnetic massless string on the background metric. Using semiclassical approach, we find the first-order (in $\hbar$ units) metric modifications and the corresponding gravitational potential and deficit angle. It is shown that, in certain region of values of coupling constant and magnetic flux, the gravitational potential and deficit angle can be positive as well as negative over all distances from the string and can even change its sign. Unlike the case of massless scalar field, the gravitational corrections were found to have short-range behavior.