Quantum fluctuation plays a key role in the parametric down-conversion in the Langevin regime. In this paper, we report the experimental realization of optical parametric down-conversion in the Langevin regime on a chip. By precisely controlling the loss inherently tied to fluctuation, we observe the asymmetric Hong-Ou-Mandel dip - a hallmark of quantum fluctuation in the fluctuation-driven PDC, and the fluctuation-induced compression of single photons by nearly one order of magnitude. These findings pave the way for the manipulation of quantum fluctuation, quantum states, and system-reservoir interaction.
@article{arxiv.2511.10556,
title = {Observation and Manipulation of Optical Parametric Down-Conversion in the Langevin Regime},
author = {Yen-Ju Chen and Chun-Yuan Cheng and Tien-Dat Pham and Tzu-An Chen and Chang-Hau Kuo and Yen-Hung Chen and Chih-Sung Chuu},
journal= {arXiv preprint arXiv:2511.10556},
year = {2025}
}