Effect of multimode entanglement on lossy optical quantum metrology

Knott, P A, Proctor, T J, Nemoto, Kae, Dunningham, J A and Munro, W J (2014) Effect of multimode entanglement on lossy optical quantum metrology. Physical Review A, 90 (3). 033846. ISSN 1050-2947

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Abstract

In optical interferometry multimode entanglement is often assumed to be the driving force behind quantum enhanced measurements. Recent work has shown this assumption to be false: single-mode quantum states perform just as well as their multimode entangled counterparts. We go beyond this to show that when photon losses occur, an inevitability in any realistic system, multimode entanglement is actually detrimental to obtaining quantum enhanced measurements. We specifically apply this idea to a superposition of coherent states, demonstrating that these states show a robustness to loss that allows them to significantly outperform their competitors in realistic systems. A practically viable measurement scheme is then presented that allows measurements close to the theoretical bound, even with loss. These results promote an alternate way of approaching optical quantum metrology using single-mode states that we expect to have great implications for the future.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics
Q Science > QC Physics > QC0170 Atomic physics. Constitution and properties of matter Including molecular physics, relativity, quantum theory, and solid state physics
Depositing User: Jacob Dunningham
Date Deposited: 05 Jun 2015 12:05
Last Modified: 18 Mar 2017 17:42
URI: http://sro.sussex.ac.uk/id/eprint/54287

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