Scalar particle production in a simple Horndeski theory

Understand

The scalar particle production through a scalar field non-minimally coupled with geometry is investigated in the context of a spatially homogeneous and isotropic universe.

• In this paper, in order to study the evolution of particle production over time in the case of analytical solutions, we focus on a simple Horndeski theory.
• We first suppose that the universe is dominated by a scalar field and derive the energy conservation condition.
• Then from the thermodynamic point of view, the macroscopic non-conservation of the scalar field energy-momentum tensor can be explained as an irreversible production of the scalar particles.