Spacetime Variable Superstring Vacua

TL;DR

This paper explores superstring vacua with spacetime-varying internal spaces, revealing static cosmic strings with finite energy, topological invariants, and potential for defining a global time in Lorentzian spacetime.

Contribution

It introduces a novel class of superstring vacua with spacetime-dependent internal spaces and analyzes their properties, including cosmic strings and topological invariants.

Findings

Cosmic strings with finite energy per unit length are found in these vacua.

The spacetime remains smooth despite singularities in the internal space at string centers.

Self-interactions of cosmic strings are characterized in the Euclidean model.

Abstract

In a general superstring vacuum configuration, the `internal' space (sector) varies in spacetime. When this variation is non-trivial only in two space-like dimensions, the vacuum contains static cosmic strings with finite energy per unit length and which is, up to interactions with matter, an easily computed topological invariant. The total spacetime is smooth although the `internal' space is singular at the center of each cosmic string. In a similar analysis of the Wick-rotated Euclidean model, these cosmic strings acquire expected self-interactions. Also, a possibility emerges to define a global time in order to rotate back to the Lorentzian case.