Little Theories in Six and Seven Dimensions

TL;DR

This paper explores six- and seven-dimensional theories with extended supersymmetry, analyzing their BPS spectra, dualities, and their role in describing M-theory compactifications via matrix models.

Contribution

It introduces new six- and seven-dimensional theories as world-volume theories of branes, revealing their BPS spectra, duality web, and applications to Matrix theory for M-theory.

Findings

6D theories interpreted as little string theories

New string theories with 8 supercharges derived from 6D theories

Matrix descriptions of M-theory on T^6, T^5, and T^4

Abstract

We discuss theories with 16 and 8 supercharges in 6 and 7 dimensions. These theories are defined as world-volume theories of 5- and 6-branes of type II and M theories, in the limit in which bulk modes decouple. We analyze in detail the spectrum of BPS extended objects of these theories, and show that the 6 dimensional ones can be interpreted as little (non-critical) string theories. The little 5-branes of the 6 dimensional theories with 16 supercharges are used to find new string theories with 8 supercharges, which have additional group structure. We describe the web of dualities relating all these theories. We show that the theories with 16 supercharges can be used for a Matrix description of M-theory on T^6 in the general case, and that they also reproduce Matrix theory on T^5 and T^4 in some particular limit.