Experimental Test of the Relation between Coherence and Path Information

Jun Gao, Zi-Qiang Jiao, Cheng-Qiu Hu, Lu-Feng Qiao, Ruo-Jing Ren, Hao Tang, Zhi-Hao Ma, Shao-Ming Fei, Vlatko Vedral, and Xian-Min Jin

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Submission date: 09. Jan. 2019
Pages: 8
published in: Communications physics, 1 (2018), art-no. 89 
DOI number (of the published article): 10.1038/s42005-018-0090-8
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Abstract:
Quantum coherence stemming from the superposition behaviour of a particle beyond the classical realm, serves as one of the most fundamental features in quantum mechanics. The wave-particle duality phenomenon, which shares the same origin, has a strong relationship with quantum coherence. Recently, an elegant relation between quantum coherence and path information has been theoretically derived. Here, we experimentally test such new duality by l₁-norm measure and the minimum-error state discrimination. We prepare three classes of two-photon states encoded in polarisation degree of freedom, with one photon serving as the target and the other photon as the detector. We observe that wave-particle-like complementarity and Bagan’s equality, defined by the duality relation between coherence and path information, is well satisfied. Our results may shed new light on the original nature of wave-particle duality and on the applications of quantum coherence as a fundamental resource in quantum technologies.