Observation of PT-symmetric quantum interference

TL;DR

This paper experimentally demonstrates two-particle quantum interference in a PT-symmetric system using integrated photonic waveguides, revealing counterintuitive bunching effects and advancing the understanding of nonlocal PT-symmetric quantum mechanics.

Contribution

First experimental observation of two-particle quantum interference in a PT-symmetric system using integrated photonics.

Findings

PT-symmetric bunching of indistinguishable photons shows counterintuitive features

Experimental results are supported by quantum master equation modeling

Work opens avenues for nonlocal PT-symmetric quantum devices

Abstract

Parity-Time (PT) symmetric quantum mechanics is a complex extension of conventional Hermitian quantum mechanics in which physical observables possess a real eigenvalue spectrum. However, an experimental demonstration of the true quantum nature of PT symmetry has been elusive thus far, as only single-particle physics has been exploited to date. In our work, we demonstrate two-particle quantum interference in a PT-symmetric system. We employ integrated photonic waveguides to reveal that PT-symmetric bunching of indistinguishable photons shows strongly counterintuitive features. We substantiate our experimental results by modelling the system by a quantum master equation, which we analytically solve using Lie algebra methods. Our work paves the way for nonlocal PT-symmetric quantum mechanics as a novel building block for future quantum devices.