Consistency between 11D and U-duality

TL;DR

This paper investigates the consistency of supermultiplet structures in 11D supergravity and U-duality in string theory, analyzing higher excited states across various compactifications to understand their compatibility.

Contribution

It provides a detailed analysis of the consistency between 11D supermultiplet structures and U-duality multiplets at higher string excitation levels, highlighting where they align and where questions remain.

Findings

Complete consistency found in several compactifications.

Some unresolved issues in certain compactifications.

Further clarification needed on D-brane relations.

Abstract

U duality transformations must act on a basis of states that form complete multiplets of the U group, at any coupling, even though the states may not be mass degenerate, as for a broken symmetry. Similarly, if superstring theory is related to a non-perturbative 11D M-theory, then an 11D supermultiplet structure is expected, even though the multiplet may contain states of different masses. We analyse the consistency between these two multiplet schemes at the higher excited string levels for various compactifications of the type IIA superstring. While we find complete consistency for a number of compactifications, there remain some unanswered questions in others. The relation to D-branes also needs further clarification.