Descent Relation of Tachyon Condensation from Boundary String Field Theory

TL;DR

The work analyzes tachyon condensation within boundary string field theory (BSFT) to understand descent relations between D-branes of decreasing dimension. It demonstrates that the tachyon potential on a lower-dimensional brane, such as the D$D_{24}$-brane, preserves the same profile as on the D$D_{25}$-brane up to dimensional reduction and a constant factor, indicating a self-similar descent structure. Using both BSFT and derivative-truncated field theory, it identifies the tachyon zero mode consistently across descents and shows that successive decays preserve the effective action form, thereby supporting Sen’s conjectures throughout the descent sequence. The findings illuminate the vacuum structure in double limits and reinforce the view that brane tensions and vacua align across cascaded tachyon condensations within BSFT.

Abstract

We analyze how lower-dimensional bosonic D-branes further decay, using the boundary string field theory. Especially we find that the effective tachyon potential of the lower-dimensional D-brane has the same profile as that of D25-brane.

Figures (1)

• Figure 1: The profile of the BSFT action $S(a,u)$. The D24-brane is expressed as the stationary point $a,u\to\infty$ along the ridge (\ref{['statcond']}).