Narrow Results

In this paper we analyze the vacuum expectation values of the field squared and the energy-momentum tensor associated to a massive scalar field in a higher dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary conditions on the surface orthogonal to the string.

Combined effects on the Casimir-Polder potential due to a cosmic string and coaxial metallic cylindrical shell are investigated. For the both regions inside and outside the shell, the potential is decomposed into pure string and shell-induced parts. In a special case of an isotropic polarizability tensor, the Casimir-Polder force in the interior region is attractive with respect to the shell. In the exterior region the force is attractive near the shell and repulsive at large distances from the shell.

In this paper we evaluate the Wightman functions associated with a massive quantum scalar field in de Sitter and anti-de Sitter spacetimes in the presence of a cosmic string. Having these functions we calculate the corresponding renormalized vacuum expectation values of the field squared and present the behavior of the contributions induced by the cosmic string as function of the proper distance to it for different values of the parameter which codify the presence of this linear topological defect.

We analyze the bosonic current densities induced by a magnetic flux running along an idealized cosmic string considering that the coordinate along its axis is compactified. We also consider the presence of a magnetic flux enclosed by the compactificatified axis. To develop this analysis, we calculate the complete set of normalized bosonic wave functions obeying a quasiperiodicity condition along the compactified dimension. We show that in this context only the azimuthal and axial currents take place.

We study axion strings with the electroweak gauge flux in the DFSZ axion model and show that these strings, called electroweak axions, exhibit superconductivity without fermionic zero modes. We also show that the primordial magnetic field in the early universe can induce a large electric current along the string. A pair of the strings carrying such a large current feels a net attractive force between them and can form a Y-shaped junction in the early universe, whose formation probability is roughly estimated to be 1/2.