Problems and hopes in nonsymmetric gravity

TL;DR

This paper analyzes the stability of linearized nonsymmetric gravity theories in cosmological settings, identifies a stable form, and proposes a massive antisymmetric field as a dark matter candidate.

Contribution

It derives a stable form of the linearized nonsymmetric gravity Lagrangian and explores its implications for quantum fluctuations and dark matter.

Findings

Stable form of the linearized NGT Lagrangian identified.

Quantum fluctuations of the B-field can account for dark matter.

A specific mass range for the B-field makes it a viable dark matter candidate.

Abstract

We consider the linearized nonsymmetric theory of gravitation (NGT) within the background of an expanding universe and near a Schwarzschild mass. We show that the theory always develops instabilities unless the linearized nonsymmetric lagrangian reduces to a particular simple form. This form contains a gauge invariant kinetic term, a mass term for the antisymmetric metric-field and a coupling with the Ricci curvature scalar. This form cannot be obtained within NGT. Based on the linearized lagrangian we know to be stable, we consider the generation and evolution of quantum fluctuations of the antisymmetric gravitational field (B-field) from inflation up to the present day. We find that a B-field with a mass m ~ 0.03(H_I/10^(13)GeV)^4 eV is an excellent dark matter candidate.