Cosmological particle creation in states of low energy

TL;DR

This paper investigates particle creation in cosmological models using low energy states, revealing oscillatory behavior in particle production during exponential expansion, with rigorous calculation methods.

Contribution

It introduces a rigorous method for calculating relative particle production between low energy states in cosmological spacetimes, highlighting oscillations in exponential expansion.

Findings

Particle production oscillates in exponential expansion.

The method for calculation is fully rigorous.

Numerical approximations are used only at the computational stage.

Abstract

The recently proposed states of low energy provide a well-motivated class of reference states for the quantized linear scalar field on cosmological Friedmann-Robertson-Walker spacetimes. The low energy property of a state is localized close to some value of the cosmological time coordinate. We present calculations of the relative cosmological particle production between a state of low energy at early time and another such state at later time. In an exponentially expanding Universe, we find that the particle production shows oscillations in the spatial frequency modes. The basis of the method for calculating the relative particle production is completely rigorous. Approximations are only used at the level of numerical calculation.