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Multiphoton quantum metrology with neither pre- nor post-selected measurements



Chenglong You, Mingyuan Hong, Peter Bierhorst, Adriana Lita, Scott Glancy, Steven Kolthammer, Emanuel Knill, Sae Woo Nam, Richard Mirin, Omar Magana-Loaiza, Thomas Gerrits


The quantum statistical fluctuations of the electromagnetic field establish fundamental limits on the sensitivity of optical measurements. This fundamental limit, known as the shot-noise limit, imposes constraints on classical technologies, which can be lifted by quantum technologies. In this regard, the possibility of using every photon produced by quantum sources of light to estimate small physical parameters, beyond the shot-noise limit, constitutes one of the main goals of quantum optics. Here, we contribute to this goal by experimentally demonstrating multiphoton quantum-enhanced phase estimation. For the first time, we demonstrate a quantum enhancement in the estimation of a broad range of optical phases with neither pre- nor post-selected measurements. This is achieved through the ecient design of a source of spontaneous parametric down-conversion in combination with photon-number-resolving detection. The robustness of two-mode squeezed vacuum states against loss allows us to outperform path-entanglement metrology schemes, in which the loss of a single photon is enough to remove all phase information from a quantum state. Our work is important for quantum technologies that rely on multiphoton interference such as quantum imaging, boson sampling and quantum networks.
Nature Photonics


quantum enhanced sensing, quantum metrology, transition edge sensors


You, C. , Hong, M. , Bierhorst, P. , Lita, A. , Glancy, S. , Kolthammer, S. , Knill, E. , Nam, S. , Mirin, R. , Magana-Loaiza, O. and Gerrits, T. (2021), Multiphoton quantum metrology with neither pre- nor post-selected measurements, Nature Photonics, [online], (Accessed May 27, 2024)


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Created October 21, 2021, Updated April 9, 2024