Quantum-enhanced Doppler lidar

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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npj Quantum Information, Volume 8, issue 1
We propose a quantum-enhanced lidar system to estimate a target’s radial velocity, which employs squeezed and frequency-entangled signal and idler beams. We compare its performance against a classical protocol using a coherent state with the same pulse duration and energy, showing that quantum resources provide a precision enhancement in the estimation of the velocity of the object. We identify three distinct parameter regimes characterized by the amount of squeezing and frequency entanglement. In two of them, a quantum advantage exceeding the standard quantum limit is achieved assuming no photon losses. Additionally, we show that an optimal measurement to attain these results in the lossless case is frequency-resolved photon counting. Finally, we consider the effect of photon losses for the high-squeezing regime, which leads to a constant factor quantum advantage higher than 3 dB in the variance of the estimator, given a roundtrip lidar-to-target-to-lidar transmissivity larger than 50%.
Funding Information: We thank Robert Jonsson, Göran Johansson and Benjamin Huard for insightful discussions. We acknowledge financial support from Basque Government QUANTEK project from ELKARTEK program (KK-2021/00070) and the Basque Government project IT1470-22, Spanish Ramón y Cajal Grant RYC-2020-030503-I and the project grant PID2021-125823NA-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe” and “ERDF Invest in your Future”, as well as from QMiCS (820505) and OpenSuperQ (820363) projects of the EU Flagship on Quantum Technologies, and the EU FET-Open projects Quromorphic (828826) and EPIQUS (899368). M.R. acknowledges support from UPV/EHU PhD Grant PIF21/289. M.W. acknowledges support from the National Science Foundation under Grant CCF-1956211. R.D.C. acknowledges support from the Marie Skłodowska Curie fellowship number 891517 (MSC-IF Green- MIQUEC), the Alexander von Humboldt Foundation, the Knut and Alice Wallenberg Foundation through the Wallenberg Centre for Quantum Technology (WACQT), and the Academy of Finland, grants nos. 353832, 349199. Publisher Copyright: © 2022, The Author(s). | openaire: EC/H2020/891517/EU//Green-MIQUEC
Reichert , M , Di Candia , R , Win , M Z & Sanz , M 2022 , ' Quantum-enhanced Doppler lidar ' , npj Quantum Information , vol. 8 , no. 1 , 147 . https://doi.org/10.1038/s41534-022-00662-9