A simple solution for marginal deformations in open string field theory

Understand

We derive a new open string field theory solution for boundary marginal deformations generated by chiral currents with singular self-OPE.

• The solution is algebraically identical to the Kiermaier-Okawa-Soler solution and it is gauge equivalent to the Takahashi-Tanimoto identity-based solution.
• It is wedge-based and we can analytically evaluate the Ellwood invariant and the action, reproducing the expected results from BCFT.
• By studying the isomorphism between the states of the initial and final background a dual derivation of the Ellwood invariant is also obtained.