Vacuum Values for Auxiliary String Fields

TL;DR

This paper explores the role of auxiliary string fields in light-cone gauge string field theory, showing how their non-zero expectation values induce a phase with boundary world-sheets, impacting contact interaction representations.

Contribution

It introduces the concept of non-zero expectation values for auxiliary fields, revealing a new phase with boundary world-sheets in closed-string bosonic theory.

Findings

Auxiliary fields can acquire non-zero expectation values.

Boundary world-sheets emerge in the new phase.

Contact interactions are expressed via cubic vertex contractions.

Abstract

Auxiliary string fields are introduced in light-cone gauge string field theory in order to express contact interactions as contractions of cubic vertices. The auxiliary field in the purely closed-string bosonic theory may be given a non-zero expectation value, leading to a phase in which world-sheets have boundaries.