The Hanbury-Brown and Twiss effect in inflationary cosmological perturbations

TL;DR

This paper explores the potential of using the Hanbury-Brown and Twiss effect to analyze the transition from coherence to chaos in inflationary cosmological perturbations, but finds significant differences from traditional HBT applications.

Contribution

It develops an ansatz for applying the HBT effect to inflationary perturbations and discusses the challenges due to fundamental differences from standard HBT scenarios.

Findings

The HBT effect's applicability to inflationary perturbations is uncertain.

Differences between inflationary cosmology and traditional HBT contexts are substantial.

The developed methodology faces significant conceptual challenges.

Abstract

The simplest model of inflation is based around an inflaton field that starts in a coherent false vacuum state with a positive cosmological constant, rolls slowly to the true vacuum and relaxes to it via reheating. We examine whether the scale of the transition from coherence to chaoticity can be examined via the Hanbury-Brown and Twiss (HBT) effect, in parallel with analogous problems of heavy ion physics (the ``pion laser'' and the thermalizing glasma). We develop an ansatz which contains a definition of ''chaoticity'' which parallels that of the usual setups where HBT is used. However, we also discuss the differences between the inflationary setup and more mainstream uses of HBT and conclude that these are more significant than the similarities, making the use of the developed methodology uncertain.