Abstract
Phys.Rev.D80:106005,2009 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.