Quantum cosmology in scalar-tensor theories with non-minimal coupling

Abstract

Quantization in the minisuperspace of non-minimal scalar-tensor theories leads to a partial differential equation which is non-separable. Through a conformal transformation we can recast the Wheeler-DeWitt equation in an integrable form, which corresponds to the minimal coupling case, whose general solution is known. Performing the inverse conformal transformation in the solution thus found, we can construct the corresponding solution in the original frame. This procedure can also be employed with the Bohmian trajectories. In this way, we can study the classical limit of some particular solutions of this quantum model. While the classical limit of these solutions occurs for small scale factors in the Einstein frame, it happens for small values of the scalar field non-minimally coupled to gravity in the Jordan frame, which includes large scale factors.