A Closed String Tachyon Vacuum ?

TL;DR

This paper investigates the potential existence of a closed string tachyon vacuum in bosonic string field theory by including dilaton effects, finding a critical point that suggests a non-dynamical spacetime state.

Contribution

It extends previous analyses by incorporating dilaton contributions, revealing a critical point that supports the possibility of a closed string tachyon vacuum.

Findings

A critical point persists with dilaton inclusion.

Evidence of a non-dynamical spacetime state.

Rolling solutions show dilaton runs to strong coupling.

Abstract

In bosonic closed string field theory the "tachyon potential" is a potential for the tachyon, the dilaton, and an infinite set of massive fields. Earlier computations of the potential did not include the dilaton and the critical point formed by the quadratic and cubic interactions was destroyed by the quartic tachyon term. We include the dilaton contributions to the potential and find that a critical point survives and appears to become more shallow. We are led to consider the existence of a closed string tachyon vacuum, a critical point with zero action that represents a state where space-time ceases to be dynamical. Some evidence for this interpretation is found from the study of the coupled metric-dilaton-tachyon effective field equations, which exhibit rolling solutions in which the dilaton runs to strong coupling and the Einstein metric undergoes collapse.