[7p-A410-1~9] 4.9 Quantum Optics

▲ [7p-A410-4] Multiparameter estimation with single photons
—Linearly-optically generated quantum entanglement beats the shotnoise limit

Chenglong You¹, Sushovit Adhikari¹, Yuxi Chi², 〇(B)Margarite Lynn LaBorde¹, Corey T. Matyas¹, Chenyu Zhang³, Zuen Su⁴, Tim Byrnes^5,3, Chaoyang Lu⁴, Jonathan P. Dowling^1,3, Jonathan P. Olson⁶ (1.LSU, 2.Beihang Univ., 3.NYU Shanghai, 4.USTC, 5.ECNU, 6.Harvard Univ.)

Keywords:Metrology, Multparameter, Phase Estimation

It was suggested in Ref. [Phys. Rev. Lett. 114, 170802] that optical networks with relatively inexpensive overhead—single photon Fock states, passive optical elements, and single photon detection—can show significant improvements over classical strategies for single-parameter estimation, when the number of modes in the network is small (n < 7). A similar case was made in Ref. [Phys. Rev. Lett. 111, 070403] for multi-parameter estimation, where measurement is instead made using photon-number resolving detectors. In this paper, we analytically compute the quantum Cramér-Rao bound to show these networks can have a constant-factor quantum advantage in multi-parameter estimation for even large number of modes. Additionally, we provide a simplified measurement scheme using only single-photon (on-off) detectors that is capable of approximately obtaining this sensitivity for a small number of modes.