Distinguishing between nonorthogonal quantum states of a single nuclear spin

Waldherr, G., Dada, A. C. , Neumann, P., Jelezko, F., Andersson, E. and Wrachtrup, J. (2012) Distinguishing between nonorthogonal quantum states of a single nuclear spin. Physical Review Letters, 109(18), 180501. (doi: 10.1103/PhysRevLett.109.180501)

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Abstract

An important task for quantum-information processing is optimal discrimination between two nonorthogonal quantum states, which until now has been realized only optically. Here, we present and compare experimental realizations of optimal quantum measurements for distinguishing between two nonorthogonal quantum states encoded in a single 14 N nuclear spin at a nitrogen-vacancy defect in diamond. Implemented measurement schemes are the minimum-error measurement (known as Helstrom measurement), unambiguous state discrimination using a standard projective measurement, and optimal unambiguous state discrimination [known as Ivanovic-Dieks-Peres (IDP) measurement], which utilizes a three-dimensional Hilbert space. This allows us to benchmark the IDP measurement against the standard projective measurements. Measurement efficiencies are found to be above 80% for all schemes and reach a value of 90% for the IDP measurement.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Dada, Dr Adetunmise
Authors: Waldherr, G., Dada, A. C., Neumann, P., Jelezko, F., Andersson, E., and Wrachtrup, J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Physical Review Letters
Publisher:American Physical Society
ISSN:0031-9007
ISSN (Online):1079-7114

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