Physical states at the tachyonic vacuum of open string field theory
Abstract
We illustrate a method for computing the number of physical states of open string theory at the stable tachyonic vacuum in level truncation approximation. The method is based on the analysis of the gaugefixed open string field theory quadratic action that includes FadeevPopov ghost string fields. Computations up to level 9 in the scalar sector are consistent with Sen's conjecture about the absence of physical open string states at the tachyonic vacuum. We also derive a long exact cohomology sequence that relates relative and absolute cohomologies of the BRS operator at the nonperturbative vacuum. We use this exact result in conjunction with our numerical findings to conclude that the higher ghost number nonperturbative BRS cohomologies are nonempty.
 Publication:

Nuclear Physics B
 Pub Date:
 January 2004
 DOI:
 10.1016/j.nuclphysb.2003.10.037
 arXiv:
 arXiv:hepth/0309164
 Bibcode:
 2004NuPhB.677...52G
 Keywords:

 11.25.Sq;
 Nonperturbative techniques;
 string field theory;
 High Energy Physics  Theory
 EPrint:
 43 pages, 16 eps figures, LaTeX