Metamorphosis Of Tachyon Profile In Unstable D9-Branes

TL;DR

This work extends the unstable D9-brane BSFT framework by incorporating infinite higher-derivative corrections for the tachyon and gauge fields, enabling exact solutions for a rich set of BPS brane configurations. The authors compute energies and RR-charges and find precise agreement with the expected superstring results, including previously inaccessible setups such as a bound state of (F,D6) ending on a D8-brane and the Emparan-Myers dielectric D8 in a nonsupersymmetric context. The analysis reveals that higher-derivative effects are essential in the low-energy regime of unstable branes and can drive novel metamorphoses of tachyon profiles, reproducing complex brane dynamics dynamically from tachyon condensation. The results underscore the potential of unstable brane systems to dynamically realize diverse brane configurations and motivate further study of quantum corrections, nonabelian extensions, and multi-brane realizations from tachyonic setups.

Abstract

We explored a variety of brane configurations in our previous paper within the two derivative truncation of the unstable D9-brane effective theory. In this paper we extend our previous results with emphasis on the inclusion of the higher derivative corrections for the tachyon and the gauge fields computed in the boundary string field theories. We give the exact solutions to BPS brane configurations studied in our previous paper and find remarkable exact agreements of their energies and RR-charges with the expected results. We further find a few more solutions that we could not construct in the two derivative truncations, such as a (F,D6) bound state ending on a D8-brane whose existence turns out to be due to a higher derivative effect and also the dielectric brane of Emparan and Myers as a nonsupersymmetric example. These are also in exact agreements with the results obtained in the effective theory of supersymmetric D-branes.