On the time-dependent description for the decay of unstable D-branes

TL;DR

This paper presents a world-sheet formulation for describing time-dependent decay processes of unstable D-branes in string theory, demonstrating how tachyon coupling leads to relaxation into a stationary state.

Contribution

It introduces a formalism using conformal perturbation theory to analyze slow time-dependent phenomena in string theory, specifically the decay of unstable D-branes.

Findings

Coupling of tachyons to on-shell modes causes relaxation to a stationary state.

The final state is a fixed point of the RG flow.

A general formalism for slow time-dependent processes is established.

Abstract

We discuss how to describe time-dependent phenomena in string theory like the decay of unstable D-branes with the help of the world-sheet formulation. It is shown in a nontrivial well-controlled example that the coupling of the tachyons to propagating on-shell modes which escape to infinity can lead to time-dependent relaxation into a stationary final state. The final state corresponds to a fixed point of the RG flow generated by the relevant field from which the tachyon vertex operator is constructed. On the way we set up a fairly general formalism for the description of slow time-dependent phenomena with the help of conformal perturbation theory on the world-sheet.