Experimental Demonstration of Observability and Operability of Robustness of Coherence
Wenqiang Zheng, Zhi-Hao Ma, Hengyan Wang, Shao-Ming Fei, and Xinhua Peng
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Submission date: 17. Jul. 2018
published in: Physical review letters, 120 (2018) 23, art-no. 230504
DOI number (of the published article): 10.1103/PhysRevLett.120.230504
PACS-Numbers: 03.67.Lx, 03.67.Pp, 76.60.-k
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Quantum coherence is an invaluable physical resource for various quantum technologies. As a bona fide measure in quantifying coherence, the robustness of coherence (RoC) is not only mathematically rigorous, but also physically meaningful. We experimentally demonstrate the witness-observable and operational feature of the RoC in a multi-qubit nuclear magnetic resonance system. We realize witness measurements by detecting the populations of quantum systems in one trial. The approach may also apply to physical systems compatible with ensemble or nondemolition measurements. Moreover, we experimentally show that the RoC quantifies the advantage enabled by a quantum state in a phase discrimination task.