# A Superstring Field Theory for Supergravity

## TL;DR

This paper develops a covariant superstring field theory based on the ambitwistor string, reproducing supergravity actions and scattering amplitudes, and providing a framework for perturbation theory in supergravity.

## Contribution

It introduces a new covariant superstring field theory for supergravity derived from ambitwistor strings, including an explicit operator formalism and action.

## Key findings

- Reproduces linearized supergravity gauge symmetries
- Derives spacetime actions consistent with supergravity
- Provides a perturbative framework for flat spacetime

## Abstract

A covariant closed superstring field theory, equivalent to classical ten-dimensional Type II supergravity, is presented. The defining conformal field theory is the ambitwistor string worldsheet theory of Mason and Skinner. This theory is known to reproduce the scattering amplitudes of Cachazo, He and Yuan in which the scattering equations play an important role and the string field theory naturally incorporates these results. We investigate the operator formalism description of the ambitwsitor string and propose an action for the string field theory of the bosonic and supersymmetric theories. The correct linearised gauge symmetries and spacetime actions are explicitly reproduced and evidence is given that the action is correct to all orders. The focus is on the Neveu-Schwarz sector and the explicit description of tree level perturbation theory about flat spacetime. Application of the string field theory to general supergravity backgrounds and the inclusion of the Ramond sector are briefly discussed.