On the null origin of the ambitwistor string

TL;DR

This paper demonstrates that the ambitwistor string originates from the null string, establishing a classical and quantum equivalence under specific quantization and gauge choices, and clarifies its relation to other string theories.

Contribution

It shows the null string as the classical and quantum origin of the ambitwistor string, clarifying their relationship and extending the equivalence to spinning versions.

Findings

Null string and ambitwistor string share the same constraint algebra.

Quantum equivalence depends on specific quantization scheme and gauge.

Results clarify the relationships among various string theories.

Abstract

In this paper we present the null string origin of the ambitwistor string. Classically, the null string is the tensionless limit of string theory, and so too is the Ambitwistor string. Both have as constraint algebra the Galilean Conformal Algebra in two dimensions. But something interesting happens in the quantum theory since there is an ambiguity in quantizing the null string. We show that, given a particular choice of quantization scheme and a particular gauge, the null string coincides with the ambitwistor string both classically and quantum mechanically. We also show that the same holds for the spinning versions of the null string and Ambitwistor string. With these results we clarify the relationship between the Ambitwistor string, the null string, the usual string and the Hohm-Siegel-Zwiebach theory.