Exact Supersymmetric String Solutions in Curved Gravitational Backgrounds

TL;DR

This paper constructs a new class of exact, stable superstring solutions with non-trivial backgrounds, extending known geometries and connecting to supergravity theories, relevant for understanding string dynamics in curved spacetimes.

Contribution

It introduces a novel set of exact superstring solutions based on N=4 superconformal symmetry, generalizing wormhole geometries and linking to extended supergravity models.

Findings

Derived a modular-invariant spectrum of string excitations.

Connected solutions to N=4 and N=8 gauged supergravities.

Described stable non-critical superstrings in strong coupling regimes.

Abstract

We construct a new class of exact and stable superstring solutions based on $N=4$ superconformal world-sheet symmetry. In a subclass of these, the full spectrum of string excitations is derived in a modular-invariant way. In the weak curvature limit, our solutions describe a target space with non-trivial metric and topology, and generalize the previously known (semi) wormhole. The effective field theory limit is identified in certain cases, with solutions of the $N=4$ and $N=8$ extended gauged supergravities, in which the number of space-time supersymmetries is reduced by a factor of 2 because of the presence of non-trivial dilaton, gravitational and/or gauge backgrounds. In the context of string theory, our solutions correspond to stable non-critical superstrings in the strong coupling region; the super-Liouville field couples to a unitary matter system with central charge $5\le{\hat c}_M\le 9$.