Can Hong-Ou-Mandel type quantum correlation be a test tool for quantum entanglement?

TL;DR

This paper investigates whether Hong-Ou-Mandel (HOM) anticorrelation can serve as a reliable test for quantum entanglement, using non-entangled photon pairs generated by spontaneous parametric down conversion.

Contribution

It revisits the HOM-type quantum correlation to evaluate its effectiveness as a test tool for quantum entanglement, challenging previous assumptions.

Findings

HOM anticorrelation can occur without entanglement.

SPDC photon pairs tested are not in an entangled state.

HOM effects alone may not confirm entanglement.

Abstract

Quantum technologies based on the particle nature of a photon has been progressed over the last several decades, where the fundamental quantum feature of entanglement has been tested by Hong-Ou-Mandel (HOM) type anticorrelation as well as Bell-type nonlocal correlation. Mutually exclusive quantum natures of the wave-particle duality of a single photon have been intensively investigated to understand the fundamental physics of mysterious quantum nature. Here, we revisit the HOM-type quantum correlation to answer the question whether the HOM-type anticorrelation can be a test tool for quantum entanglement. For this, a pair of spontaneous parametric down converted photons is tested for the anticorrelation of HOM effects, where the SPDC-generated photon pair is not in an entangled state.