SFT on separated D-branes and D-brane translation

TL;DR

This paper explores the properties of string fields in systems with multiple separated D-branes, using level truncation to study deformations and decay, revealing limitations in describing the full moduli space.

Contribution

It introduces a novel analysis of D-brane systems with separation, demonstrating the finite range of solutions and limitations of level truncation in Open String Field Theory.

Findings

String fields correspond to D-brane decay with changing separation.

Solutions exist only within a finite displacement range.

Open String Field Theory cannot fully describe the CFT moduli space.

Abstract

We discuss novel properties of the string field and the Open String Field Theory action arising in a system with multiple D-branes, then use the level truncation scheme to study marginal deformations and tachyon condensation in a system with two parallel but separated branes. We find string fields corresponding to D-brane decay combined with a finite change in the distance between the two D-branes. Using D-brane separation as a yardstick, we are able to continuously control the spacetime displacement of the D-branes and find that our solutions exist only for a finite range of this displacement. Thus, at least in level truncation, Open String Field Theory seems unable to describe the entire CFT moduli space.