Vacuum-induced current density from a magnetic flux threading a cosmic dispiration in $(D+1)$-dimensional spacetime

TL;DR

This paper studies the vacuum-induced current density in a higher-dimensional spacetime with a cosmic dispiration and magnetic flux, revealing novel helical and axial current components influenced by topology and geometry.

Contribution

It provides explicit expressions for vacuum currents in a complex topological spacetime, highlighting the role of screw dislocation and magnetic flux in quantum field effects.

Findings

Both azimuthal and axial current components are induced by the spacetime structure.

Currents are periodic functions of magnetic flux, depending on its fractional part.

The screw dislocation parameter regularizes the axial current at the origin.

Abstract

We investigate the vacuum-induced current density for a charged scalar field in a $(D+1)$-dimensional cosmic dispiration spacetime threaded by a magnetic flux. This background combines a cosmic string and a screw dislocation, yielding a nontrivial helical geometry. By constructing the normalized mode functions of the Klein--Gordon equation, we evaluate the Wightman function and obtain the vacuum expectation value of the current density. We show that, in addition to the azimuthal component describing a persistent current around the defect, a nonvanishing axial component is induced as a direct consequence of the helical structure of the spacetime. Both components are periodic functions of the magnetic flux, depending only on its fractional part, reflecting the Aharonov--Bohm nature of the effect. Closed expressions are obtained for both massive and massless fields in arbitrary dimensions. We demonstrate that the screw dislocation parameter plays a crucial role in the behavior of the induced currents, leading to the regularization of the axial component at the origin and controlling its magnitude. The asymptotic behavior of both components is analyzed in detail. Our results reduce to known expressions in the absence of the screw dislocation, providing a consistency check. In particular, we examine the physically relevant $(3+1)$-dimensional case, where numerical analysis reveals nontrivial features arising from the interplay between topology and gauge effects.