Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 19: Quantum Optics III
Q 19.4: Talk
Tuesday, March 7, 2017, 11:45–12:00, P 5
Distinguishability and many-particle interference — •Stefanie Barz1, Adrian Menssen1, Alex Jones1,2, Ben Metcalf1, Malte C. Tichy3, Steve Kolthammer1, and Ian A. Walmsley1 — 1Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU, United Kingdom, — 2Blackett Laboratory, Imperial College London, SW7 2BW, United Kingdom, — 3Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark,
Quantum interference of two independent particles in pure quantum states is fully described by the particles' distinguishability: the closer the particles are to being identical, the higher the degree of quantum interference. When more than two particles are involved, the situation becomes more complex and interference capability extends beyond pairwise distinguishability, taking on a surprisingly rich character. Here, we study many-particle interference using three photons. We show that the distinguishability between pairs of photons is not sufficient to fully describe the photons' behaviour in a scattering process, but that a collective phase, the triad phase, plays a role. We are able to explore the full parameter space of three-photon interference by generating heralded single photons and interfering them in a fibre tritter. Using multiple degrees of freedom---temporal delays and polarisation---we isolate three-photon interference from two-photon interference. Our experiment disproves the view that pairwise two-photon distinguishability uniquely determines the degree of non-classical many-particle interference.