Bound States of String Theory and Beyond

TL;DR

This paper explores the bound states of various fundamental objects in string theory, using a geometric approach based on null geodesic motion on specific coset spaces related to exceptional groups.

Contribution

It introduces a unified framework describing bound states of strings, D-branes, and NS-branes across type-IIA and type-IIB string theories via coset models within E(11).

Findings

Unified description of bound states across string theories

Application of coset models to string bound states

Connection to exceptional symmetry groups

Abstract

All bound states of fundamental strings, D-branes and NS-branes of string theory, both type-IIA and type-IIB, which may be described by a null geodesic motion on the coset G/K(G) where G is a group of type A, D or E embedded within E(11) are presented.