Practical quantum metrology with large precision gains in the low photon number regime

Knott, P A, Proctor, T J, Hayes, A J, Cooling, J P and Dunningham, J A (2016) Practical quantum metrology with large precision gains in the low photon number regime. Physical Review A, 93 (3). a3859. ISSN 2469-9926

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Abstract

Quantum metrology exploits quantum correlations to make precise measurements with limited particle numbers. By utilizing inter- and intra- mode correlations in an optical interferometer, we find a state that combines entanglement and squeezing to give a 7-fold enhancement in the quantum Fisher information (QFI) - a metric related to the precision - over the shot noise limit, for low photon numbers. Motivated by practicality we then look at the squeezed cat-state, which has recently been made experimentally, and shows further precision gains over the shot noise limit and a 3-fold improvement in the QFI over the optimal Gaussian state. We present a conceptually simple measurement scheme that saturates the QFI, and we demonstrate a robustness to loss for small photon numbers. The squeezed cat-state can therefore give a significant precision enhancement in optical quantum metrology in practical and realistic conditions.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics
Depositing User: Richard Chambers
Date Deposited: 23 Jun 2016 10:30
Last Modified: 07 Mar 2017 03:08
URI: http://sro.sussex.ac.uk/id/eprint/60337

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