Tachyon condensation in string field theory

TL;DR

This paper calculates the tachyon potential in open string field theory, showing that tachyon condensation cancels most of the D-brane tension, supporting the conjecture about D-brane decay.

Contribution

It provides off-shell calculations of the tachyon potential, demonstrating significant tension cancellation with increasing scalar levels, advancing understanding of tachyon condensation.

Findings

Tachyon condensation cancels about 70% of D-brane tension at the cubic potential stationary point.

Including scalars up to four mass levels increases tension cancellation to 99%.

Results support the conjecture that tachyon condensation leads to D-brane decay.

Abstract

It has been conjectured that at a stationary point of the tachyon potential for the D-brane of bosonic string theory, the negative energy density exactly cancels the D-brane tension. We evaluate this tachyon potential by off-shell calculations in open string field theory. Surprisingly, the condensation of the tachyon mode alone into the stationary point of its cubic potential is found to cancel about 70% of the D-brane tension. Keeping relevant scalars up to four mass levels above the tachyon, the energy density at the shifted stationary point cancels 99% of the D-brane tension.