Kerr-Newman stress-tensor from minimal coupling

TL;DR

This paper shows that the stress-energy tensor of Kerr-Newman black holes can be derived to all orders in spin using minimal coupling techniques, providing a new way to connect classical solutions with quantum form factors.

Contribution

It introduces a method to recover the Kerr-Newman stress tensor to all orders in spin from minimal coupling, based solely on kinematic considerations.

Findings

Stress tensor derived from minimal coupling at leading PM order

All orders in spin can be obtained from the classical limit of form factors

Provides a basis for connecting quantum form factors with classical black hole metrics

Abstract

In this paper, we demonstrate that at leading order in post Minkowskian (PM) expansion, the stress-energy tensor of Kerr-Newman can be recovered to all orders in spin from three sets of minimal coupling: the electric and gravitational minimal coupling for higher-spin particles, and the "minimal coupling" for massive spin-2 decay. These couplings are uniquely defined from kinematic consideration alone. This is shown by extracting the classical piece of the one-loop stress-energy tensor form factor, which we provide a basis that is valid to all orders in spin. The 1 PM stress tensor, and the metric in the harmonic gauge, is then recovered from the classical spin limit of the form factor.