Unoriented Minimal Type 0 Strings

TL;DR

This paper introduces a family of string equations representing unoriented minimal string theories with D-branes and R-R fluxes, exploring their non-perturbative sectors and dualities with type 0A and 0B models.

Contribution

It defines new string equations for unoriented minimal strings with background D-branes and fluxes, and establishes a non-perturbative map to type 0B models.

Findings

Existence of a well-defined non-perturbative sector.

Identification of a parameter related to background D-branes.

Duality map exchanging D-branes and fluxes.

Abstract

We define a family of string equations with perturbative expansions that admit an interpretation as an unoriented minimal string theory with background D-branes and R-R fluxes. The theory also has a well-defined non-perturbative sector and we expect it to have a continuum interpretation as an orientifold projection of the non-critical type~0A string for \hat{c}=0, the (2,4) model. There is a second perturbative region which is consistent with an interpretation in terms of background R-R fluxes. We identify a natural parameter in the formulation that we speculate may have an interpretation as characterizing the contribution of a new type of background D-brane. There is a non-perturbative map to a family of string equations which we expect to be the \hat{c}=0 type 0B string. The map exchanges D-branes and R-R fluxes. We present the general structure of the string equations for the (2,4k) type 0A models.