Work

Optimal quantum metrology of distant black bodies

Year: 2017

Type: article

Abstract: Measurements of an object's temperature are important in many disciplines, from astronomy to engineering, as are estimates of an object's spatial configuration. We present the quantum optimal estimator for the temperature of a distant body based on the black body radiation received in the far-field. We also show how to perform separable quantum optimal estimates of the spatial configuration of a distant object, i.e. imaging. In doing so we necessarily deal with multi-parameter quantum estimation of incompatible observables, a problem that is poorly understood. We compare our optimal observables to the two mode analogue of lensed imaging and find that the latter is far from optimal, even when compared to measurements which are separable. To prove the optimality of the estimators we show that they minimise the cost function weighted by the quantum Fisher information---this is equivalent to maximising the average fidelity between the actual state and the estimated one.

Source: Quantum

DOI: 10.22331/q-2017-07-26-21

Authors: Mark E. Pearce, Earl T. Campbell, Pieter Kok

Institution: University of Sheffield

Language: English

Topic: Quantum Information and Cryptography

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $215

Funder: Engineering and Physical Sciences Research Council