Wave nature-based nonlocal correlation via projection measurements between space-like separated interferometric systems

TL;DR

This paper demonstrates a wave nature-based nonlocal correlation between space-like separated interferometers using polarization projection measurements, challenging traditional views on photon indistinguishability and nonlocality.

Contribution

It introduces a coherence-based nonlocal correlation method using polarization projections in space-like separated NMZIs, expanding understanding of quantum nonlocality.

Findings

Phase-sensitive nonlocal correlation achieved

Indistinguishability concept extended beyond entangled photons

Coincidence detection reveals coherence-based nonlocal effects

Abstract

Indistinguishability in quantum mechanics is an essential concept to understanding mysterious quantum features such as self-interference of a single photon and two-photon nonlocal correlation. Delayed-choice experiments are for the cause-effect violation via post-measurements of photons in an interferometric system. Recently, a macroscopic version of the delayed-choice experiments has been demonstrated using the classical means of Poisson distributed photons in a noninterfering Mach-Zehnder interferometer (NMZI). Here, a coherence version of the nonlocal correlation is presented using the wave nature of photons in space-like separated orthogonally polarized NMZIs. For this, polarization-basis projections of the pair of NMZI output photons onto a set of polarizers are measured coincidently, where each output photon comprises orthogonal polarization bases. Because of the coherence feature of the output photons via coincidence detection, a phase sensitive nonlocal correlation is achieved. As a result, indistinguishability limited to a single or entangled photon pairs needs to be reconsidered with basis (polarization) randomness for the nonlocal correlation.