# Torsional Newton Cartan gravity from non-relativistic strings

## TL;DR

This paper develops a string theory framework in torsional Newton-Cartan geometry, deriving conditions for Weyl invariance, and reveals how torsion influences gravitational laws and string dynamics.

## Contribution

It extends the Polyakov action to include matter fields in TNC geometry and analyzes Weyl invariance, critical dimension, and gravitational implications.

## Key findings

- Critical dimension of 25 for TNC string theory
- Newton's law emerges from Weyl invariance conditions
- Torsion introduces mass and advection terms in gravity

## Abstract

We study propagation of closed bosonic strings in torsional Newton-Cartan geometry based on a recently proposed Polyakov type action derived by dimensional reduction of the ordinary bosonic string along a null direction. We generalize the Polyakov action proposal to include matter, i.e. the 2-form and the 1-form that originates from the Kalb-Ramond field and the dilaton. We determine the conditions for Weyl invariance which we express as the beta-function equations on the worldsheet, in analogy with the usual case of strings propagating on a pseudo-Riemannian manifold. The critical dimension of the TNC space-time turns out to be 25. We find that Newton's law of gravitation follows from the requirement of quantum Weyl invariance in the absence of torsion. Presence of the 1-form requires torsion to be non vanishing. Torsion has interesting consequences, in particular it yields a mass term and an advection term in the generalized Newton's law. U(1) mass invariance of the theory is an important ingredient in deriving the beta functions.