Large Marginal Deformations in String Field Theory

TL;DR

This paper uses level truncation in string field theory to analyze large marginal deformations, revealing a finite effective potential range and exploring its relation to conformal field theory parameters.

Contribution

It provides a detailed numerical study of large marginal deformations in string field theory and investigates the effective potential's behavior at higher levels of approximation.

Findings

Effective potential becomes flatter with higher approximation levels.

The effective potential exists only within a finite range of the massless field.

Exploration of the relation between finite effective potential range and conformal field theory parameters.

Abstract

We use the level truncation scheme to obtain accurate descriptions of open bosonic string field configurations corresponding to large marginal deformations such as background Wilson lines. To do so, we solve for all fields as functions of the massless string field, and confirm that the effective potential of the massless field becomes increasingly flat as the level of approximation is increased. Surprisingly, as a result of the merging of two branches of the solution - one originating at zero tachyon vev and the other originating at the tachyonic vacuum - this effective potential exists only for a finite range of values of the massless field. We use the D1 to D0 brane marginal transition on a circle to explore the possibility that this finite range corresponds to the infinite range of the conformal field theory parameter describing marginal deformations, but are unable to arrive at a definitive conclusion.