Possible detection of nonclassical primordial gravitational waves with Hanbury Brown - Twiss interferometry

TL;DR

This paper proposes using Hanbury Brown - Twiss interferometry to detect nonclassical primordial gravitational waves, highlighting that classical sources during inflation can facilitate this detection, especially for frequencies above 10 kHz.

Contribution

It introduces a novel method to detect nonclassicality of primordial gravitational waves using HBT interferometry in cosmology.

Findings

Detection of nonclassical PGWs is possible with HBT interferometry.

Classical sources during inflation enable nonclassicality detection.

Higher frequency PGWs (>10 kHz) are more detectable.

Abstract

We consider possible detection of nonclassicality of primordial gravitational waves (PGWs) by applying Hanbury Brown - Twiss (HBT) interferometry to cosmology. We characterize the nonclassicality of PGWs in terms of sub-Poissonian statistics that can be measured by the HBT interferometry. We show that the presence of classical sources during inflation makes us possible to detect nonclassical PGWs with the HBT interferometry. We present two examples that realize the classical sources during inflation. It turns out that PGWs with frequencies higher than 10 kHz enable us to detect their nonclassicality.