research

Qubit metrology and decoherence

Abstract

Quantum properties of the probes used to estimate a classical parameter can be used to attain accuracies that beat the standard quantum limit. When qubits are used to construct a quantum probe, it is known that initializing nn qubits in an entangled "cat state," rather than in a separable state, can improve the measurement uncertainty by a factor of 1/n1/\sqrt{n}. We investigate how the measurement uncertainty is affected when the individual qubits in a probe are subjected to decoherence. In the face of such decoherence, we regard the rate RR at which qubits can be generated and the total duration Ï„\tau of a measurement as fixed resources, and we determine the optimal use of entanglement among the qubits and the resulting optimal measurement uncertainty as functions of RR and Ï„\tau.Comment: 24 Pages, 3 Figure

    Similar works

    Full text

    thumbnail-image

    Available Versions

    Last time updated on 01/04/2019