Propagating waves in an extremal black string

TL;DR

This paper analyzes wave propagation in an extremal black string within string theory, revealing that only the graviton propagates while the dilation and axion do not.

Contribution

It demonstrates that in a (2+1)-dimensional extremal black string background, the graviton is the sole propagating mode, clarifying the mode structure in this setting.

Findings

Graviton is the only propagating mode.

Dilation and axion are non-propagating.

Provides insight into mode dynamics in black string backgrounds.

Abstract

We investigate the black string in the context of the string theories. It is shown that the graviton is the only propagating mode in the (2+1)--dimensional extremal black string background. Both the dilation and axion turn out to be non-propagating modes.