CLASSICAL SPLITTING OF FUNDAMENTAL STRINGS

TL;DR

This paper presents exact classical solutions for string splitting, showing it reduces action and models a decay process, with analysis in flat space and gravitational backgrounds, highlighting the effects of strong gravitational fields.

Contribution

It provides the first exact classical solutions describing string splitting, demonstrating action reduction and decay dynamics in flat and curved spacetimes.

Findings

Splitting strings have smaller action than non-splitting ones.

String splitting models a decay process into smaller strings.

Gravitational fields amplify the action difference in splitting solutions.

Abstract

We find exact solutions of the string equations of motion and constraints describing the {\em classical}\ splitting of a string into two. We show that for the same Cauchy data, the strings that split have {\bf smaller} action than the string without splitting. This phenomenon is already present in flat space-time. The mass, energy and momentum carried out by the strings are computed. We show that the splitting solution describes a natural decay process of one string of mass $M$ into two strings with a smaller total mass and some kinetic energy. The standard non-splitting solution is contained as a particular case. We also describe the splitting of a closed string in the background of a singular gravitational plane wave, and show how the presence of the strong gravitational field increases (and amplifies by an overall factor) the negative difference between the action of the splitting and non-splitting solutions.