Open String Theory in 1+1 Dimensions

TL;DR

This paper demonstrates that open string theory in 1+1 dimensions is exactly solvable at tree level, revealing unique features and a connection to free fermions, with implications for understanding quark dynamics and black hole solutions.

Contribution

It provides the first exact solution of open string theory in 1+1 dimensions, highlighting its differences from the closed string case and introducing a fermionic interpretation.

Findings

Open string S-matrix describes free fermions.

Existence of an exact vacuum solution as a charged black hole.

Open string theory exhibits unique features not present in closed string theory.

Abstract

We show that tree level open two dimensional string theory is exactly solvable; the solution exhibits some unusual features, and is qualitatively different from the closed case. The open string ``tachyon'' S -- matrix describes free fermions, which can be interpreted as the quarks at the ends of the string. These ``quarks'' live naturally on a lattice in space-time. We also find an exact vacuum solution of the theory, corresponding to a charged black hole.