The Tachyon Potential in Witten's Superstring Field Theory

TL;DR

Sen's conjecture on tachyon condensation is tested within the NS sector of Witten's cubic superstring field theory using the Kostelecky-Samuel level truncation up to level 2. The tachyon potential is shown to have no minimum, and this behavior persists when including higher modes up to the truncation level studied. The work also uncovers structural issues, such as divergences from picture-changing insertions and the absence of a twist symmetry, which distinguish this framework from Berkovits' formulation. The authors suggest that Berkovits' approach remains a more robust candidate for describing off-shell superstring interactions.

Abstract

We study the tachyon potential in the NS sector of Witten's cubic superstring field theory. In this theory, the pure tachyon contribution to the potential has no minimum. We find that this remains the case when higher modes up to level two are included.