Quantum decoherence of primordial perturbations through nonlinear scaler-tensor interaction

TL;DR

This paper demonstrates that nonlinear scalar-tensor interactions during inflation cause quantum decoherence of primordial perturbations, with a derived master equation describing this process.

Contribution

It identifies the dominant interaction Hamiltonian and derives the master equation explaining quantum decoherence during inflation.

Findings

Decoherence occurs at horizon crossing due to nonlinear interactions

The dominant interaction Hamiltonian is characterized

A master equation for the decoherence process is derived

Abstract

Scaler and tensor perturbations couple nonlinearly with each other in the Einstein-Hilbert action. We show that such interaction naturally leads to the quantum decoherence of the primordial perturbations during inflation at horizon crossing. The dominant interaction Hamiltonian contributing to decoherence is identified and the master equation responsible for the decohering process is derived.