The energy-carrying velocity and rolling of tachyons of unstable D-branes

TL;DR

This paper explores the energy and momentum properties of tachyons from unstable D-branes, revealing their unique velocity characteristics and dynamic behavior near potential hills, which enhances understanding of tachyon condensation.

Contribution

It introduces the concept of energy-carrying tachyons with superluminal phase velocities and analyzes their motion and potential states in the tachyon potential landscape.

Findings

Tachyons carry energy and momentum at velocity β = c^2/v.

Tachyons can pass over or bounce back from the potential hill.

A marginal solution exists where tachyons stay at the potential top.

Abstract

It is shown that the tachyons which originate from unstable D-branes carry energy and momentum at the velocity $\beta = c^2/v,$ where $v$ is the phase velocity which is greater than $c.$ For an observer who moves with the velocity $\beta,$ tachyon is observed to be moving from one of the ground states of the tachyon potential to the potential hill. It is found that tachyon either passes over the hill or bounces back to the original ground state. Another possible solution is the case which is margial to these, that is tachyon reaches to the top of the potential hill and stays there forever.