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arXiv · 2309.09841

Photonic quantum metrology with variational quantum optical non-linearities

A. Muñoz de las Heras·C. Tabares·J. T. Schneider·L. Tagliacozzo·D. Porras·A. González-Tudela
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Abstract

Photonic quantum metrology harnesses quantum states of light, such as NOON or Twin-Fock states, to measure unknown parameters beyond classical precision limits. Current protocols suffer from two severe limitations that preclude their scalability: the exponential decrease in fidelities (or probabilities) when generating states with large photon numbers due to gate errors, and the increased sensitivity of such states to noise. Here, we develop a deterministic protocol combining quantum optical non-linearities and variational quantum algorithms that provides a substantial improvement on both fronts. First, we show how the variational protocol can generate metrologically-relevant states with a small number of operations which does not significantly depend on photon-number, resulting in exponential improvements in fidelities when gate errors are considered. Second, we show that such states offer a better robustness to noise compared to other states in the literature. Since our protocol harnesses interactions already appearing in state-of-the-art setups, such as cavity QED, we expect that it will lead to more scalable photonic quantum metrology in the near future.

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A. Muñoz de las Heras, C. Tabares, J. T. Schneider, L. Tagliacozzo, D. Porras, A. González-Tudela. 2023-09-18. Photonic quantum metrology with variational quantum optical non-linearities. https://doi.org/10.1103/physrevresearch.6.013299

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