Experimental test of the relation between coherence and path information

• Published in: Communications physics 2018-11, Vol.1 (1), Article 89
• Main Authors: Gao, Jun, Jiao, Zhi-Qiang, Hu, Cheng-Qiu, Qiao, Lu-Feng, Ren, Ruo-Jing, Tang, Hao, Ma, Zhi-Hao, Fei, Shao-Ming, Vedral, Vlatko, Jin, Xian-Min
• Format: Article
• Language: English
• Subjects: 639/766/400/482; 639/766/483/1139; 639/766/483/2802; 639/766/483/3925; 639/766/483/481; Coherence; Error analysis; Photons; Physics; Physics and Astronomy; Quantum mechanics; Quantum phenomena; Quantum physics
• ISSN: 2399-3650; 2399-3650
• DOI: 10.1038/s42005-018-0090-8

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 l 1 -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. Quantum coherence represents one of the most fundamental features in quantum mechanics and is closely linked to the concept of wave-particle duality. The authors report an experimental realisation which proves the relation between coherence and path information as recently derived theoretically.