Fundamental strings and NS5-branes from unstable D-branes in supergravity

TL;DR

This paper demonstrates how non-supersymmetric p-brane solutions in supergravity can interpolate between unstable D-branes, fundamental strings, and NS5-branes, providing a closed string perspective on tachyon condensation.

Contribution

It shows that supergravity solutions can represent transitions between various unstable D-branes, fundamental strings, and NS5-branes, supporting the open string tachyon condensation conjecture.

Findings

Supergravity solutions interpolate between unstable D-branes and fundamental strings.

Solutions also connect unstable D-branes with NS5-branes for p ≤ 5.

Supports the idea that tachyon condensation leads to solitons representing various branes.

Abstract

By using the non-supersymmetric $p$-brane solutions delocalized in arbitrary number of transverse directions in type II supergravities, we show how they can be regarded as interpolating solutions between unstable D$p$-branes (a non-BPS D-brane or a pair of coincident D-brane-antiD-brane) and fundamental strings and also between unstable D$p$-branes and NS5-branes. We also show that some of these solutions can be regarded as interpolating solutions between NS5/$\bar{\rm NS}$5 and D$p$-branes (for $p \leq 5$). This gives a closed string description of the tachyon condensation and lends support to the conjecture that the open string theory on unstable D-branes at the tachyonic vacuum has soliton solutions describing not only the lower dimensional BPS D-branes, but also the fundamental strings as well as the NS5-branes.