Finite temperature bosonic charge and current densities in compactified cosmic string spacetime

Abstract

In this paper we study the expectation values of the induced charge and current densities for a massive bosonic field with nonzero chemical potential in the geometry of a higher dimensional compactified cosmic string with magnetic fluxes, along the string core and also enclosed by the compactified direction, in thermal equilibrium at finite temperature $T$. These densities are calculated by decomposing them into the vacuum expectation values and finite temperature contributions coming from the particles and antiparticles. The only nonzero components correspond to the charge, azimuthal and axial current densities. By using the Abel-Plana formula, we decompose the components of the densities into the part induced by the cosmic string and the one by the compactification. The charge density is an odd function of the chemical potential and even periodic function of the magnetic flux with a period equal to the quantum flux. Moreover, the azimuthal (axial) current density is an even function of the chemical potential and an odd (even) periodic function of the magnetic flux with the same period. In this paper our main concern is the thermal effect on the charge and current densities, including some limiting cases, the low and high temperature approximations. We show that in all cases the temperature enhances the induced densities.