Exact null tachyons from RG flows

TL;DR

This paper constructs exact two-dimensional conformal field theories representing null tachyon profiles linked to RG flows, providing a precise correspondence between tachyon variation and the worldsheet scale.

Contribution

It introduces a method to generate exact CFT solutions from any 2D RG flow, connecting tachyon profiles with RG equations through first order null coordinate equations.

Findings

Exact null tachyon solutions derived from RG flows.

Tachyon equations of motion match RG flow equations.

Null coordinate dynamics encode worldsheet scale evolution.

Abstract

We construct exact 2d CFTs, corresponding to closed string tachyon and metric profiles invariant under shifts in a null coordinate, which can be constructed from any 2d renormalization group flow. These solutions satisfy first order equations of motion in the conjugate null coordinate. The direction along which the tachyon varies is identified precisely with the worldsheet scale, and the tachyon equations of motion are the RG flow equations.