Tachyon Kinks

TL;DR

This paper explores static solitonic solutions in the tachyonic effective action of unstable D2-branes, revealing various kink configurations influenced by electromagnetic fields and their implications for D-brane interpretations.

Contribution

It provides a detailed analysis of tachyon kink solutions with electromagnetic fields, extending understanding of D-brane decay and soliton structures in string theory.

Findings

Periodic array of tachyon kink-antikinks in pure tachyonic theory

Electromagnetic fields enable diverse solutions including topological kinks and bounces

Tensions of kinks relate to D-brane tensions and electric fields

Abstract

We study Born-Infeld type tachyonic effective action of unstable D2-brane with a runaway potential and find rich structure of static regular solitonic solutions. There exists only periodic array of tachyon kink-antikinks in pure tachyonic theory, however, in the presence of electromagnetic fields, solutions include periodic arrays, topological tachyon kinks, half kink, and bounces. Computed tension of each kink or single unit of the periodic array has $T_{1}=\sqrt{2}\pi T_{2}$ or that with a multiplicative factor depending on electric field. When both electric and magnetic fields are turned on, fundamental string charge density has a confined component in addition to a constant piece. These evidences imply that the obtained codimension-1 objects are likely to be interpreted as D1-brane (and D1F1) or array of D1$\bar{{\rm D}}1$ (and D1F1-$\bar{{\rm D}}1$F1) as was the case without the electromagnetic fields. Generalization to unstable D$p$-branes is straightforward.