More D-branes in the Nappi-Witten background

TL;DR

This paper classifies various D-branes in the Nappi-Witten background, revealing new types such as D-instantons, flat Euclidean D-strings, and curved D-membranes, all characterized as conjugacy classes.

Contribution

It extends previous classifications by identifying additional D-brane configurations, including D-instantons and curved membranes, in the Nappi-Witten background.

Findings

Discovery of D-instantons, flat Euclidean D-strings, and curved D-membranes.

All identified branes correspond to (twisted) conjugacy classes in the Nappi-Witten group.

Enhanced understanding of D-brane spectrum in this background.

Abstract

We re-examine the problem of determining the possible D-branes in the Nappi-Witten background. In addition to the known branes, we find that there are also D-instantons, flat euclidean D-strings and curved D-membranes admitting parallel spinors, all of which can be interpreted as (twisted) conjugacy classes in the Nappi-Witten group.