Vacuum currents in partially compactified Rindler spacetime with an application to cylindrical black holes

TL;DR

This paper analyzes vacuum-induced currents for a charged scalar field in Rindler spacetime with compactified dimensions, revealing their dependence on magnetic flux, horizon proximity, and asymptotic spacetime geometry, with implications for cylindrical black holes.

Contribution

It provides explicit expressions for vacuum currents in partially compactified Rindler spacetime and compares them with Minkowski vacuum results, including near-horizon and asymptotic behaviors.

Findings

Vacuum current density is periodic in magnetic flux.

Currents vanish at the Rindler horizon.

Asymptotic analysis links compactification to black hole horizon and AdS geometry.

Abstract

The vacuum expectation value of the current density for a charged scalar field is investigated in Rindler spacetime with a part of spatial dimensions compactified to a torus. It is assumed that the field is prepared in the Fulling-Rindler vacuum state. For general values of the phases in the periodicity conditions and the lengths of compact dimensions, the expressions are provided for the Hadamard function and vacuum currents. The current density along compact dimensions is a periodic function of the magnetic flux enclosed by those dimensions and vanishes on the Rindler horizon. The obtained results are compared with the corresponding currents in the Minkowski vacuum. The near-horizon and large-distance asymptotics are discussed for the vacuum currents around cylindrical black holes. In the near-horizon approximation the lengths of compact dimensions are determined by the horizon radius. At large distances from the horizon the geometry is approximated by a locally anti-de Sitter spacetime with toroidally compact dimensions and the lengths of compact dimensions are determined by negative cosmological constant.