Vacuum properties of nonsymmetric gravity in de Sitter space

TL;DR

This paper investigates how quantum effects of a massive antisymmetric tensor field influence de Sitter space, showing that loop effects can cause the effective cosmological constant to relax to zero, altering the infrared behavior of gravity.

Contribution

It introduces a renormalization group improved effective action for nonsymmetric gravity theories and demonstrates the quantum relaxation of the cosmological constant in de Sitter space.

Findings

Hubble parameter relaxes to zero due to quantum effects

Quantum loop effects alter the infrared sector of gravity

Effective cosmological constant becomes insensitive to initial value

Abstract

We consider quantum effects of a massive antisymmetric tensor field on the dynamics of de Sitter space-time. Our starting point is the most general, stable, linearized Lagrangian arising in nonsymmetric gravitational theories (NGTs), where part of the antisymmetric field mass is generated by the cosmological term. We construct a renormalization group (RG) improved effective action by integrating out one loop vacuum fluctuations of the antisymmetric tensor field and show that, in the limit when the RG scale goes to zero, the Hubble parameter -- and thus the effective cosmological constant -- relaxes rapidly to zero. We thus conclude that quantum loop effects in de Sitter space can dramatically change the infrared sector of the on-shell gravity, making the expansion rate insensitive to the original (bare) cosmological constant.