Beating the Standard Quantum Limit with Four-Entangled Photons

By T. Nagata, R. Okamoto, Jeremy Lloyd O'Brien, K. Sasaki, S. Takeuchi. Science, 2007

700 citations recorded by the source corpus.

Precision measurements are important across all fields of science. In particular, optical phase measurements can be used to measure distance, position, displacement, acceleration, and optical path length. Quantum entanglement enables higher precision than would otherwise be possible. We demonstrated an optical phase measurement with an entangled four-photon interference visibility greater than the threshold to beat the standard quantum limit—the limit attainable without entanglement. These results open the way for new high-precision measurement applications.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/fc3dc7f9382d0d4c30fbfe5717cc9e5b8647d1ba

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Imaging with quantum states of light (2019, background): “[116] T.”
A perspective on multiparameter quantum metrology: From theoretical tools to applications in quantum imaging (2019, background): “This builds over significant effort devoted to the measurement of optical phases with quantum light [117].”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “The twin-Fock state has been used to overcome the standard quantum limit in an optical interferometer using up to n = 2 photons per pair (Krischek et al., 2011; Nagata et al., 2007; Xiang et al., 2011).”
Manipulation of multiphoton entanglement in waveguide quantum circuits (2009, background): “small amount of mode mismatch as the only two free parameters that modify equations (10) and (11).”
Quantum metrology and its application in biology (2014, background): “ntexts, with continuous measurements on bright elds often compared to the 8 quantum noise limit [35, 16, 29, 36, 12], and photon counting measurements typically compared to the standard quantum limit [15, 37, 38]. Although the quantum noise limit is widely used, there is no clear consensus as to its”
Entanglement-enhanced measurement of a completely unknown phase (2010, background): “Previous investigations into exploiting entanglement-enhanced sensitivity have used a ‘top-down’ approach, starting with a theoretical knowledge of the optimal states and determining how to approximate these experimentally by constructing complex circuits to filter them from more easily produced sta”