Four Dimensional Supergravity from String Theory

TL;DR

This paper derives the N=1 supergravity action in four dimensions directly from string theory, connecting fundamental string excitations to gravitational and gravitino fields in curved spacetime.

Contribution

It presents a novel derivation of four-dimensional N=1 supergravity from a superstring framework starting with a Nambu-Goto bosonic string.

Findings

Derivation of supergravity action from string theory.

Identification of graviton and gravitino in string excitations.

Confirmation of Lorentz invariance of the energy tensor.

Abstract

A derivation of N=1 supergravity action from string theory is presented. Starting from a Nambu-Goto bosonic string, matter field is introduced to obtain a superstring in four dimension. The excitation quanta of this string contain graviton and the gravitino. Using the principle of equivalence, the action in curved space time are found and the sum of them is the Deser-Zumino N=1 supergravity action. The energy tensor is Lorentz invariant due to supersymmetry.