The nonperturbative closed string tachyon vacuum to high level

TL;DR

This paper computes the closed bosonic string field theory potential at high levels, revealing oscillations around a nonzero negative value and proposing a new truncation scheme for better convergence to estimate the potential's depth.

Contribution

It introduces a novel truncation scheme in string field theory calculations that improves convergence and provides a more precise estimate of the tachyon vacuum potential.

Findings

Potential oscillates around a negative value after level four

A new truncation scheme accelerates convergence of potential values

Estimated depth of the tachyon potential is more precise

Abstract

We compute the action of closed bosonic string field theory at quartic order with fields up to level ten. After level four, the value of the potential at the minimum starts oscillating around a nonzero negative value, in contrast with the proposition made in [5]. We try a different truncation scheme in which the value of the potential converges faster with the level. By extrapolating these values, we are able to give a rather precise value for the depth of the potential.