Crossing exceptional points in non-Hermitian quantum systems
Abstract
Exceptional points facilitate peculiar dynamics in non-Hermitian systems. Yet, in photonics, they have mainly been studied in the classical realm. In this work, we reveal the behavior of two-photon quantum states in non-Hermitian systems across the exceptional point. We probe the lossy directional coupler with an indistinguishable two-photon input state and observe distinct changes of the quantum correlations at the output as the system undergoes spontaneous breaking of parity-time symmetry. Moreover, we demonstrate a switching in the quantum interference of photons directly at the exceptional point, where Hong-Ou-Mandel dips are transformed into peaks by a change of basis. These results show that quantum interference and exceptional points are linked in curious ways that can now be further explored.
Cite
@article{arxiv.2407.12578,
title = {Crossing exceptional points in non-Hermitian quantum systems},
author = {Friederike U. J. Klauck and Matthias Heinrich and Alexander Szameit and Tom A. W. Wolterink},
journal= {arXiv preprint arXiv:2407.12578},
year = {2025}
}
Comments
12 pages, 4 figures