Relevant Deformations in Open String Field Theory: a Simple Solution for Lumps

Understand

We propose a remarkably simple solution of cubic open string field theory which describes inhomogeneous tachyon condensation.

• The solution is in one-to-one correspondence with the IR fixed point of the RG-flow generated in the two--dimensional world-sheet theory by integrating a relevant operator with mild enough OPE on the boundary.
• It is shown how the closed string overlap correctly captures the shift in the closed string one point function between the UV and the IR limits of the flow.
• Examples of lumps in non-compact and compact transverse directions are given.