  Quantum theory of a test field on a quantum cosmological spacetime may be
viewed as a theory of the test field on an emergent classical background. In
such a case, the resulting dressed metric for the field propagation is a
function of the quantum fluctuations of the original geometry. When the
backreaction is negligible, massive modes can experience an anisotropic Bianchi
type I background. The field modes propagating on such a
quantum-gravity-induced spacetime can then unveil interesting phenomenological
consequences of the super-Planckian scales, such as gravitational particle
production. The aim of this paper is to address the issue of gravitational
particle production associated to the massive modes in such an anisotropic
dressed spacetime. By imposing a suitable adiabatic condition on the vacuum
state and computing the energy density of the created particles, the
significance of the particle production on the dynamics of the universe in
Planck era is discussed.
