Excitations on wedge states and on the sliver

TL;DR

This paper investigates ghost excitations on the sliver state in string field theory to evaluate the effective action and potential, providing evidence for the convergence of level truncation near the tachyon vacuum.

Contribution

It develops a method using the generalized gluing and resmoothing theorem to evaluate the effective action for excitations on wedge and sliver states, analyzing symmetries and convergence.

Findings

Effective potential values are close at different truncation levels.

Level truncation converges for excitations on the sliver.

Supports the conjecture of string field theory actions around the tachyon vacuum.

Abstract

We study ghost number one excitations on the sliver to investigate the solution of string field actions around the tachyon vacuum. The generalized gluing and resmoothing theorem is used to develop a method for evaluating the effective action for excitations on both the wedge states and the sliver state. We analyze the discrete symmetries of the resulting effective action for excitations on the sliver. The gauge unfixed effective action till level two excitations on the sliver is evaluated. This is done for the case with the BRST operator $c_0$ and $c_0 + (c_2 + c_{-2})/2$ with excitations purely in the ghost sector. We find that the values of the effective potential at the local maximum lie close by for the zeroth and the second level of approximation. This indicates that level truncation in string field theory around the tachyon vacuum using excitations on the sliver converges for both choices of the BRST operator. It also provides evidence for the conjectured string field theory actions around the tachyon vacuum.