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Robustness of Coherence: An Operational and Observable Measure of Quantum Coherence

Napoli, Carmine; Bromley, Thomas R.; Cianciaruso, Marco; Piani, Marco; Johnston, Nathaniel; Adesso, Gerardo


Carmine Napoli

Thomas R. Bromley

Marco Cianciaruso

Marco Piani

Nathaniel Johnston


Quantifying coherence is an essential endeavour for both quantum foundations and quantum technologies. Here the robustness of coherence is defined and proven a full monotone in the context of the recently introduced resource theories of quantum coherence. The measure is shown to be observable, as it can be recast as the expectation value of a coherence witness operator for any quantum state. The robustness of coherence is evaluated analytically on relevant classes of states, and an efficient semidefinite program that computes it on general states is given. An operational interpretation is finally provided: the robustness of coherence quantifies the advantage enabled by a quantum state in a phase discrimination task.


Napoli, C., Bromley, T. R., Cianciaruso, M., Piani, M., Johnston, N., & Adesso, G. (2016). Robustness of Coherence: An Operational and Observable Measure of Quantum Coherence. Physical Review Letters, 116(15), Article 150502.

Journal Article Type Article
Acceptance Date Mar 3, 2016
Online Publication Date Apr 12, 2016
Publication Date Apr 12, 2016
Deposit Date Feb 24, 2017
Publicly Available Date Feb 24, 2017
Journal Physical Review Letters
Print ISSN 0031-9007
Electronic ISSN 1079-7114
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 116
Issue 15
Article Number 150502
Public URL
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