D-brane Spectra of Nonsupersymmetric, Asymmetric Orbifolds and Nonperturbative Contributions to the Cosmological Constant

TL;DR

This paper investigates nonperturbative features of nonsupersymmetric asymmetric orbifolds in type IIA string theory, focusing on D-brane spectra, dualities with heterotic models, and implications for the cosmological constant.

Contribution

It derives boundary states for nonsupersymmetric D-branes and explores their duality relations, revealing nonperturbative effects and spectrum mismatches in these models.

Findings

Identification of non BPS multiplets under duality

Insights into boson-fermion mismatch via nonperturbative states

Boundary state construction for nonsupersymmetric D-branes

Abstract

We study nonperturbative aspects of asymmetric orbifolds of type IIA, focussing on models that allow a dual perturbative heterotic description. In particular we derive the boundary states that describe the nonsupersymmetric D-branes of the untwisted sector and their zero mode spectra. These we use to demonstrate, how some special non BPS multiplets are identified under the duality map, and give some indications, how the mismatch of bosons and fermions in the perturbative heterotic spectrum is to be interpreted in terms of the nonperturbative degrees of freedom on the type IIA side.