Excited D-branes and Supergravity Solutions

TL;DR

This paper explores supergravity solutions related to excited D-branes, revealing how boundary condition deformations lead to dilaton charge and connecting these to tachyon condensation processes in string theory.

Contribution

It identifies the role of boundary condition deformations in supergravity solutions and links them to tachyonic excitations in D-brane systems.

Findings

The parameter c_1 is related to the dilaton charge.

Deformed D-branes arise from tachyon condensation.

Boundary condition deformations explain the dilaton charge presence.

Abstract

We investigate the general solution with the symmetry ISO(1,p)xSO(9-p) of Type II supergravity (the three-parameter solution) from the viewpoint of the superstring theory. We find that one of the three parameters (c_1) is closely related to the ``dilaton charge'' and the appearance of the dilaton charge is a consequence of deformations of the boundary condition from that of the boundary state for BPS D-branes. We give three examples of the deformed D-branes by considering the tachyon condensation from systems of D-\bar{D}p-branes, unstable D9-branes and unstable D-instantons to the BPS saturated Dp-branes, respectively. We argue that the deformed systems are generally regarded as tachyonic and/or massive excitations of the open strings on Dp-\bar{D}p-brane systems.