Comments on the RG‐Flow in Open String Field Theory

We define a metric on the KBc‐subalgebra modulo gauge and describe the worldsheet RG‐flow as the gradient flow of the action of cubic open string field theory, where the flow lines are kink‐solitons. In particular, for a constant tachyon the gradient flow equations are equivalent to the RG‐equations. Additionally, a more general family of gradient flow lines is presented, which describes the RG‐flow from the conformal manifold of the D‐brane under tachyon condensation. We also derive the stability operator of our solution and show that that the zero‐modes reflect the invariance of the flow under such marginal perturbations. In fact, the beta function is colinear to our solution such that it describes geodesics from the conformal manifold to the tachyon vacuum with respect to .