Multiparameter estimation with single photons

Chenglong You, Sushovit Adhikari, Yuxi Chi, Margarite L. LaBorde, Corey T. Matyas, Chenyu Zhang, Zuen Su, Tim Byrnes, Chaoyang Lu, Jonathan P. Dowling, Jonathan P. Olson

(Submitted on 17 Jun 2017)

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 Cram\'er-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.

Comments:	13 pages, 3 figures
Subjects:	Quantum Physics (quant-ph)
Cite as:	arXiv:1706.05492 [quant-ph]
	(or arXiv:1706.05492v1 [quant-ph] for this version)