Experimental Demonstration of Observability and Operability of Robustness of Coherence

Wenqiang Zheng, Zhihao Ma, Hengyan Wang, Shao-Ming Fei, and Xinhua Peng

Phys. Rev. Lett. 120, 230504 – Published 8 June 2018

Abstract

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 multiqubit 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.

Received 22 October 2017
Revised 3 February 2018

DOI:https://doi.org/10.1103/PhysRevLett.120.230504

Physics Subject Headings (PhySH)

Quantum coherence & coherence measures Quantum control Resource theories

Quantum Information, Science & Technology

Authors & Affiliations

Wenqiang Zheng¹, Zhihao Ma², Hengyan Wang^3,*, Shao-Ming Fei^4,5,†, and Xinhua Peng^6,7,8,‡

¹Center for Optics & Optoelectronics Research, Collaborative Innovation Center for Information Technology in Biological and Medical Physics, College of Science, Zhejiang University of Technology, Hangzhou 310023, China
²Department of Mathematics, Shanghai Jiaotong University, Shanghai 200240, China
³Department of Physics, Zhejiang University of Science and Technology, Hangzhou 310023, China
⁴School of Mathematical Sciences, Capital Normal University, Beijing 100048, China
⁵Max-Planck-Institute for Mathematics in the Sciences, 04103 Leipzig, Germany
⁶CAS Key Laboratory of Microscale Magnetic Resonance and Department of Modern Physics, University of Science and Technology of China, Hefei 230026, China
⁷Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
⁸Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University, Changsha 410081, China

^*hywang@zust.edu.cn
^†feishm@cnu.edu.cn
^‡xhpeng@ustc.edu.cn

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Vol. 120, Iss. 23 — 8 June 2018

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