Quantizing multi-pronged open string junction

TL;DR

This paper develops a covariant quantization framework for multi-pronged open bosonic string junctions, revealing a complex algebraic structure that ensures a ghost-free physical state space.

Contribution

It introduces a novel quantization approach for string junctions involving twisted bosons and demonstrates the absence of ghosts in the resulting Hilbert space.

Findings

No ghosts in the physical state space

Algebra of twisted bosons includes a Virasoro subalgebra

Framework extends beyond static analysis

Abstract

Covariant quantization of multi-pronged open bosonic string junction is studied beyond static analysis. Its excited states are described by a set of ordinary bosons as well as some sets of twisted bosons on the world-sheet. The system is characterized by a certain large algebra of twisted type which includes a single Virasoro algebra as a subalgebra. By properly defining the physical states, one can show that there are no ghosts in the Hilbert space.