STRING STRING DUALITY CONJECTURE IN SIX DIMENSIONS AND CHARGED SOLITONIC STRINGS

TL;DR

This paper explores the duality between type IIA and heterotic string theories in six dimensions, showing how charged solitonic strings can be constructed in type IIA and confirming aspects of the string-string duality conjecture.

Contribution

It demonstrates the existence of a 24-parameter family of charged solitonic string solutions in type IIA theory, supporting the duality with heterotic strings and clarifying charge-carrying mechanisms.

Findings

Charged heterotic strings are realized as non-singular solitons in type IIA.

Type IIA fundamental strings do not admit charged deformations, aligning with theoretical expectations.

Supports the string-string duality conjecture in six dimensions.

Abstract

It has recently been conjectured that the type IIA string theory compactified on K3 and the heterotic string theory compactified on a four dimensional torus describe identical string theories. The fundamental heterotic string can be regarded as a non-singular soliton solution of the type IIA string theory with a semi-infinite throat. We show that this solution admits 24 parameter non-singular deformation describing a fundamental heterotic string carrying electric charge and current. The charge is generated due to the coupling of the gauge fields to the anti-symmetric tensor field, and not to an explicit source term. This clarifies how soliton solutions carrying charge under the Ramond-Ramond fields can be constructed in the type IIA theory, and provides further support to the string string duality conjecture. Similarly, the fundamental type IIA string can be regarded as a non-singular solution of the heterotic string theory with a semi-infinite throat, but this solution does not admit any deformation representing charged string. This is also consistent with the expectation that a fundamental type IIA string does not carry any charge that couples to the fields originating in the Ramond-Ramond sector.