Bohmian Quantization of a Nonminimal Coupling Cosmology

TL;DR

This paper applies Bohmian quantum cosmology to a nonminimal derivative coupling model, finding non-singular, accelerating solutions compatible with gravitational wave constraints, expanding understanding of quantum effects in such theories.

Contribution

It introduces a Bohmian quantization approach to NDC cosmology, revealing non-singular, accelerated solutions consistent with gravitational wave constraints.

Findings

Existence of non-singular solutions with accelerated expansion.

Quantum solutions compatible with gravitational wave speed constraints.

Phase space analysis supports the viability of quantum bouncing and cyclic models.

Abstract

In a recent paper we studied the cosmology of Nonminimal Derivative Coupling (NDC) between gravity and a scalar field, which is a non-trivial class of Horndeski. We have shown that it presents a variety of solutions for the scale factor, but there are gravitational waves only for a very restrictive range in phase space, and primordial waves are completely forbidden classically in NDC. In this paper, we apply canonical quantization with the Bohm-de Broglie interpretation to that theory for a small value of the nonminimal coupling constant. We then study two quantum solutions of the Wheeler-DeWitt equation that lead to the perturbation of bouncing and cyclic solutions. By the analysis of the phase space obtained from the guidance equations of Bohm-de Broglie, we study the phase space determined by the scale factor and the scalar field for those quantum solutions in order to investigate three main aspects of that theory: the existence of non-singular solutions, the regions of accelerated expansion, and the regions compatible with the gravitational waves speed constraint. We conclude that there are non-singular solutions with an accelerated expansion period compatible with the constraint.