@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}
}
@article{JahnkeGiesAssmannetal.2016,
  author    = {Jahnke, Frank and Gies, Christopher and Aßmann, Marc and Bayer, Manfred and Leymann, H.A.M. and Foerster, Alexander and Wiersig, Jan and Schneider, Christian and Kamp, Martin and H{\"o}fling, Sven},
  title     = {Giant photon bunching, superradiant pulse emission and excitation trapping in quantum-dot nanolasers},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  number    = {11540},
  doi       = {10.1038/ncomms11540},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166144},
  year      = {2016},
  abstract  = {Light is often characterized only by its classical properties, like intensity or coherence. When looking at its quantum properties, described by photon correlations, new information about the state of the matter generating the radiation can be revealed. In particular the difference between independent and entangled emitters, which is at the heart of quantum mechanics, can be made visible in the photon statistics of the emitted light. The well-studied phenomenon of superradiance occurs when quantum-mechanical correlations between the emitters are present. Notwithstanding, superradiance was previously demonstrated only in terms of classical light properties. Here, we provide the missing link between quantum correlations of the active material and photon correlations in the emitted radiation. We use the superradiance of quantum dots in a cavity-quantum electrodynamics laser to show a direct connection between superradiant pulse emission and distinctive changes in the photon correlation function. This directly demonstrates the importance of quantum-mechanical correlations and their transfer between carriers and photons in novel optoelectronic devices.},
  language  = {en}
}