Numerical twist-even SU(1,1)-singlet solutions in open string field theory around the identity-based solution

TL;DR

This paper constructs numerical twist-even SU(1,1)-singlet solutions in open string field theory around the identity-based TT solution, revealing solutions analogous to known branes and analyzing their properties.

Contribution

It introduces numerical solutions in the TT background that resemble double and ghost branes, expanding understanding of solution space around identity-based solutions.

Findings

Solutions exhibit similar $a$-dependence to known brane solutions

Complex solutions tend to become real at higher levels for some parameters

Real solutions do not significantly clarify double brane interpretation

Abstract

Using the level truncation method, we construct numerical solutions, which are twist even and SU(1,1) singlet, in the theory around the Takahashi-Tanimoto identity-based solution (TT solution) with a real parameter $a$ in the framework of bosonic open string field theory. We find solutions corresponding to "double brane" and "ghost brane" solutions which were constructed by Kudrna and Schnabl in the conventional theory around the perturbative vacuum. Our solutions show somewhat similar $a$-dependence to tachyon vacuum and single brane solutions, which we found in the earlier works. In this sense, we might be able to expect that they are consistent with the conventional interpretation of $a$-dependence of the TT solution. We observe that numerical complex solutions at low levels become real ones at higher levels for some region of the parameter $a$. However, these real solutions do not so improve interpretation for double brane.