Unconditional and robust quantum metrological advantage beyond NOON states
Abstract
Quantum metrology employs quantum resources to enhance the measurement sensitivity beyond that can be achieved classically. While multi-photon entangled NOON states can in principle beat the shot-noise limit and reach the Heisenberg limit, high NOON states are difficult to prepare and fragile to photon loss which hinders it from reaching unconditional quantum metrological advantages. Here, we combine the idea of unconventional nonlinear interferometers and stimulated emission of squeezed light, previously developed for photonic quantum computer Jiuzhang, to propose and realize a new scheme that achieves a scalable, unconditional, and robust quantum metrological advantage. We observe a 5.8(1)-fold enhancement above the shot-noise limit in the Fisher information extracted per photon, without discounting for photon loss and imperfections, which outperforms ideal 5-NOON states. The Heisenberg-limited scaling, the robustness to external photon loss, and the ease-to-use of our method make it applicable in practical quantum metrology at low photon flux regime.
Cite
@article{arxiv.2302.00940,
title = {Unconditional and robust quantum metrological advantage beyond NOON states},
author = {Jian Qin and Yu-Hao Deng and Han-Sen Zhong and Li-Chao Peng and Hao Su and Yi-Han Luo and Jia-Min Xu and Dian Wu and Si-Qiu Gong and Hua-Liang Liu and Hui Wang and Ming-Cheng Chen and Li Li and Nai-Le Liu and Chao-Yang Lu and Jian-Wei Pan},
journal= {arXiv preprint arXiv:2302.00940},
year = {2023}
}
Comments
To be published, with an independent and simultaneous submission on arXiv:2111.09756