DF-strings from D3${\bar {\bf D}}$3 as Cosmic Strings

TL;DR

This paper investigates classical solutions of DF-strings in a D3-D3bar system using a Dirac-Born-Infeld effective theory, revealing two types of solutions with different tachyon behaviors and implications for cosmic string formation.

Contribution

It introduces a detailed analysis of straight global and local DF-string solutions with quantized vorticity, classified by tachyon amplitude growth, and explores their properties in the D3-D3bar system.

Findings

Identified two types of DF-string solutions based on tachyon amplitude growth.

Found that a constant electric flux makes DF-strings thicker.

Demonstrated that these cosmic DF-strings are stable against inflation effects.

Abstract

We study Dirac-Born-Infeld type effective field theory of a complex tachyon and U(1)$\times$U(1) gauge fields describing a D3${\bar {\rm D}}$3 system. Classical solutions of straight global and local DF-strings with quantized vorticity are found and are classified into two types by the asymptotic behavior of the tachyon amplitude. For sufficiently large radial distances, one has linearly-growing tachyon amplitude and the other logarithmically-growing tachyon amplitude. A constant radial electric flux density denoting the fundamental-string background makes the obtained DF-strings thick. The other electric flux density parallel to the strings is localized, which represents localization of fundamental strings in the D1-F1 bound states. Since these DF-strings are formed in the coincidence limit of the D3${\bar {\rm D}}$3, these cosmic DF-strings are safe from inflation induced by the approach of the separated D3 and ${\bar {\rm D}}3$.