Particle creation in a colliding plane wave spacetime: wave packet quantization

TL;DR

This paper employs wave packet mode quantization to analyze massless scalar particle creation in a colliding plane wave spacetime, revealing a thermal spectrum with temperature linked to the focusing time of the waves.

Contribution

It introduces wave packet modes for simplifying mode propagation analysis in colliding plane wave spacetimes, providing new insights into particle creation spectra.

Findings

Particle creation exhibits a thermal spectrum.

The temperature is inversely proportional to the focusing time.

Wave packet modes simplify the analysis of mode propagation.

Abstract

We use wave packet mode quantization to compute the creation of massless scalar quantum particles in a colliding plane wave spacetime. The background spacetime represents the collision of two gravitational shock waves followed by trailing gravitational radiation which focus into a Killing-Cauchy horizon. The use of wave packet modes simplifies the problem of mode propagation through the different spacetime regions which was previously studied with the use of monocromatic modes. It is found that the number of particles created in a given wave packet mode has a thermal spectrum with a temperature which is inversely proportional to the focusing time of the plane waves and which depends on the mode trajectory.