Fundamental Strings in Open String Theory at the Tachyonic Vacuum

TL;DR

This paper demonstrates that at the tachyonic vacuum, the D-brane's world-volume theory admits string solitons governed by the Nambu-Goto action, indicating restored higher-dimensional Poincare invariance and the presence of closed strings.

Contribution

It provides evidence that the tachyonic vacuum restores (25+1)-dimensional Poincare invariance and contains closed string excitations within open string field theory.

Findings

Existence of solitonic string solutions at the tachyonic vacuum.

Dynamics governed by Nambu-Goto action in (25+1) dimensions.

Indications of closed string excitations in open string field theory.

Abstract

We show that the world-volume theory on a D-p-brane at the tachyonic vacuum has solitonic string solutions whose dynamics is governed by the Nambu-Goto action of a string moving in (25+1) dimensional space-time. This provides strong evidence for the conjecture that at this vacuum the full (25+1) dimensional Poincare invariance is restored. We also use this result to argue that the open string field theory at the tachyonic vacuum must contain closed string excitations.