The RR charges of A-type Gepner models

TL;DR

This paper investigates the RR charges in A-type Gepner models, revealing that standard branes do not account for all charges, and introduces matrix factorisations to identify the missing D-branes, including generalized permutation branes.

Contribution

It demonstrates that additional matrix factorisations are needed to fully describe RR charges in Gepner models, expanding the understanding of D-brane configurations.

Findings

Standard branes do not account for all RR charges.

Matrix factorisations generate the full lattice of charges.

Generalized permutation branes are introduced as additional solutions.

Abstract

It is shown that the RR charges of Gepner models are not all accounted for by the usual tensor product and permutation branes. In order to characterise the missing D-branes we study the matrix factorisation approach to the description of D-branes for Gepner models. For each of the A-type models we identify a set of matrix factorisations whose charges generate the full lattice of quantised charges. The additional factorisations that are required correspond to generalised permutation branes.