Energy Momentum Tensor and Marginal Deformations in Open String Field Theory

TL;DR

This paper develops a systematic approach to relate marginal boundary deformations in conformal field theory to classical solutions in open string field theory, using the energy-momentum tensor and boundary state analysis.

Contribution

It introduces a method to connect boundary deformation parameters with classical solutions in open string field theory via energy-momentum tensor construction.

Findings

Established a relation between boundary deformation parameters and classical solutions.

Demonstrated vanishing pressure for tachyon lump solutions on larger circles.

Validated the approach by analyzing boundary states and energy-momentum tensors.

Abstract

Marginal boundary deformations in a two dimensional conformal field theory correspond to a family of classical solutions of the equations of motion of open string field theory. In this paper we develop a systematic method for relating the parameter labelling the marginal boundary deformation in the conformal field theory to the parameter labelling the classical solution in open string field theory. This is done by first constructing the energy-momentum tensor associated with the classical solution in open string field theory using Noether method, and then comparing this to the answer obtained in the conformal field theory by analysing the boundary state. We also use this method to demonstrate that in open string field theory the tachyon lump solution on a circle of radius larger than one has vanishing pressure along the circle direction, as is expected for a codimension one D-brane.