Tachyon Kink Solutions Research Articles

Configurational entropy of tachyon kinks on unstable Dp-branes

We consider tachyon effective theory with Born–Infeld electromagnetic fields and investigate the configurational entropy of the various tachyon kink solutions. We find that the configurational entropy starts at a minimum value and saturates to a maximum value as the negative pressure of pure tachyonic field increases. In particular, when an electric field is turned on and its magnitude is larger than or equal to the critical value, we find the configurational entropy has a global minimum, which is related to the predominant tachyonic states.

Deforming tachyon kinks and tachyon potentials

In this paper we investigate deformation of tachyon potentials and tachyon kink solutions. We consider the deformation of a DBI type action with gauge and tachyon fields living on D1-brane and D3-brane world-volume. We deform tachyon potentials to get other consistent tachyon potentials by using properly a deformation function depending on the gauge field components. Resolutions of singular tachyon kinks via deformation and applications of deformed tachyon potentials to scalar cosmology scenario are discussed.

BPS D-branes from an unstable D-brane in a curved background

We find exact tachyon kink solutions of Dirac-Born-Infeld--type effective action describing an unstable D5-brane with a world volume gauge field turned on in a curved background. The background of interest is the ten-dimensional lift of the Salam-Sezgin vacuum and, in the asymptotic limit, it approaches ${\mathrm{R}}^{1,4}\ifmmode\times\else\texttimes\fi{}{\mathrm{T}}^{2}\ifmmode\times\else\texttimes\fi{}{\mathrm{S}}^{3}$. The solutions are identified as composites of lower-dimensional D-branes and fundamental strings, and, in the BPS limit, they become a D4D2F1 composite wrapped on ${\mathrm{R}}^{1,2}\ifmmode\times\else\texttimes\fi{}{\mathrm{T}}^{2}$ where ${\mathrm{T}}^{2}$ is inside ${\mathrm{S}}^{3}$. In one class of solutions we find an infinite degeneracy with respect to a constant magnetic field along the direction of the Neveu-Schwarz--Neveu-Schwarz field on ${\mathrm{S}}^{3}$.

Delocalized, non-SUSY p-branes, tachyon condensation and tachyon matter

We construct non-supersymmetric $p$-brane solutions of type II supergravities in arbitrary dimensions ($d$) delocalized in one of the spatial transverse directions. By a Wick rotation we convert these solutions into Euclidean $p$-branes delocalized in the transverse time-like direction. The former solutions in $d=10$ nicely interpolate between the $(p+1)$-dimensional non-BPS D-branes and the $p$-dimensional BPS D-branes very similar to the picture of tachyon condensation for the tachyonic kink solution on the non-BPS D-branes. On the other hand the latter solutions interpolate between the $(p+1)$-dimensional non-BPS D-branes and the tachyon matter supergravity configuration very similar to the picture of rolling tachyon on the non-BPS D-branes.

On the effective action of a space-like brane

Starting from the non-BPS D(p+1)-brane action, we derive an effective action in (p+1) space dimensions by studying the fluctuations of various bosonic fields around the time-like tachyonic kink solution (obtained by Wick rotation of the space-like tachyonic kink solution) of the non-BPS brane. In real time this describes the dynamics of a space-like or Euclidean brane in (p+1) dimensions containing a Dirac–Born–Infeld (DBI) part and an Wess–Zumino (WZ) part. The WZ part is purely imaginary and so the action is complex if it represents the source of the time-dependent background of type II string theory, i.e., S-brane. On the other hand, the WZ part as well as the action is real if it represents the source in type II∗ string theory, i.e., E-brane. The DBI part is the same as obtained before using different method. This is then further illustrated by considering brane probe in space-like brane background.

DESCENT RELATIONS AMONG BOSONIC D-BRANES

We show that the tachyonic kink solution on a pair of D-p-branes in the bosonic string theory can be identified with the D-(p-1)-brane of the same theory. We also speculate on the possibility of obtaining the D-(p-1)-brane as a tachyonic lump on a single D-p-brane. We suggest a possible reinterpretation of the first result which unifies these two apparently different descriptions of the D-(p-1)-brane.