@article{LuedersPukropRozasetal.2021,
  author    = {L{\"u}ders, Carolin and Pukrop, Matthias and Rozas, Elena and Schneider, Christian and H{\"o}fling, Sven and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc},
  title     = {Quantifying Quantum Coherence in Polariton Condensates},
  series = {PRX Quantum},
  volume    = {2},
  journal   = {PRX Quantum},
  doi       = {10.1103/PRXQuantum.2.030320},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-369644},
  year      = {2021},
  abstract  = {We theoretically and experimentally investigate quantum features of an interacting light-matter system from a multidisciplinary perspective, combining approaches from semiconductor physics, quantum optics, and quantum-information science. To this end, we quantify the amount of quantum coherence that results from the quantum superposition of Fock states, constituting a measure of the resourcefulness of the produced state for modern quantum protocols. This notion of quantum coherence from quantum-information theory is distinct from other quantifiers of nonclassicality that have previously been applied to condensed-matter systems. As an archetypal example of a hybrid light-matter interface, we study a polariton condensate and implement a numerical model to predict its properties. Our simulation is confirmed by our proof-of-concept experiment in which we measure and analyze the phase-space distributions of the emitted light. Specifically, we drive a polariton microcavity across the condensation threshold and observe the transition from an incoherent thermal state to a coherent state in the emission, thus confirming the buildup of quantum coherence in the condensate itself.},
  language  = {en}
}