T-symmetry in String Geometry Theory

TL;DR

The paper addresses how dualities among perturbatively stable vacua arise in a non-perturbative framework by introducing $T$-symmetry in dimensionally reduced string geometry theories. It shows that spatial reduction yields a T-duality between $S_{IIA}$ and $S_{IIB}$ backgrounds, while temporal reduction reveals a separate nonperturbative symmetry not visible in perturbative string theories. The results imply all $d=10$ supergravities can be obtained as consistent truncations from string geometry and that exotic branes emerge naturally via an underlying $O(d,d)$ structure. This work suggests a nonperturbative mechanism to reconcile T-duality with quantum gravity constraints by treating $T$-symmetry as an effective discrete symmetry of the dimensionally reduced theory.

Abstract

String geometry theory is one of the candidates of non-perturbative formulation of string theory. In this paper, we have shown that dimensionally reduced string geometry theories have what we call T-symmetry. In case of the dimensional reduction in space-like directions, the T-symmetry transformation gives the T-dual transformation between the type IIA and IIB perturbative vacua. In case of the dimensional reduction in the direction of string geometry time $\barτ$, the T-symmetry transformation is independent of the T-dual transformation, and gives a symmetry that cannot be seen in the perturbative string theories.