Survey of the Tachyonic Lump in Bosonic String Field Theory

TL;DR

This paper investigates tachyonic lump solutions in bosonic string field theory, analyzing their properties, gauge independence, and fluctuation spectra, providing evidence that these lumps correspond to lower-dimensional D-branes.

Contribution

It offers a detailed analysis of tachyonic lumps, demonstrating gauge independence of their size and tension, and identifies fluctuation spectra supporting their interpretation as D-branes.

Findings

Lump size and tension are gauge-independent at level (2,4).

Fluctuation spectrum includes a tachyon with m^2=-0.96.

Results support the identification of lumps with lower-dimensional D-branes.

Abstract

We study some properties of the tachyonic lumps in the level truncation scheme of bosonic cubic string field theory. We find that several gauges work well and that the size of the lump as well as its tension is approximately independent of these gauge choices at level (2,4). We also examine the fluctuation spectrum around the lump solution, and find that a tachyon with m^2=-0.96 and some massive scalars appear on the lump world-volume. This result strongly supports the conjecture that a codimension 1 lump solution is identified with a D-brane of one lower dimension within the framework of bosonic cubic string field theory.