Dimension-changing exact solutions of string theory

TL;DR

This paper introduces classical solutions in string theory that enable dynamical transitions between theories of different dimensions and supersymmetry properties via closed-string tachyon condensation, expanding the understanding of string theory moduli space.

Contribution

It presents new exact solutions demonstrating dimension-changing transitions in string theory, including non-supersymmetric and spacelike linear dilaton backgrounds, driven by worldsheet one-loop effects.

Findings

Transitions between different string theories and dimensions are possible.

The string-frame metric and dilaton gradient adjust during transitions.

The worldsheet central charge remains constant at 15 during these processes.

Abstract

Superstring theories in the critical dimension D=10 are connected to one another by a well-explored web of dualities. In this paper we use closed-string tachyon condensation to connect the supersymmetric moduli space of the critical superstring to non-supersymmetric string theories in more than ten dimensions. We present a new set of classical solutions that exhibit dynamical transitions between string theories in different dimensions, with different degrees of stability and different amounts of spacetime supersymmetry. In all examples, the string-frame metric and dilaton gradient readjust themselves during the transition. The central charge of the worldsheet theory remains equal to 15, even as the total number of dimensions changes. This phenomenon arises entirely from a one-loop diagram on the string worldsheet. Allowed supersymmetric final states include half-BPS vacua of type II and SO(32) heterotic string theory. We also find solutions that bypass the critical dimension altogether and proceed directly to spacelike linear dilaton theories in dimensions greater than or equal to two.