title: Real-space collapse of a polariton condensate.
abstract: Microcavity polaritons are two-dimensional bosonic fluids with strong nonlinearities, composed of coupled photonic and electronic excitations. In their condensed form, they display quantum hydrodynamic features similar to atomic Bose-Einstein condensates, such as long-range coherence, superfluidity and quantized vorticity. Here we report the unique phenomenology that is observed when a pulse of light impacts the polariton vacuum: the fluid which is suddenly created does not splash but instead coheres into a very bright spot. The real-space collapse into a sharp peak is at odd with the repulsive interactions of polaritons and their positive mass, suggesting that an unconventional mechanism is at play. Our modelling devises a possible explanation in the self-trapping due to a local heating of the crystal lattice, that can be described as a collective polaron formed by a polariton condensate. These observations hint at the polariton fluid dynamics in conditions of extreme intensities and ultrafast times.
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Dominici
authors.affiliation: Spin Optics Laboratory, Saint Petersburg State University, 198504 St Petersburg, Russia.
authors.forename: M
authors.identifier: http://orcid.org/0000-0002-9382-8936
authors.initials: M
authors.lastname: Petrov
authors.affiliation: Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Matuszewski
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Ballarini
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.
authors.forename: M
authors.initials: M
authors.lastname: De Giorgi
authors.affiliation: Física Teorica de la Materia Condensada, UAM, 28049 Madrid, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Colas
authors.affiliation: Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK.|Laboratoire Kastler Brossel, UPMC-Paris 6, ÉNS et CNRS, 75005 Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Cancellieri
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.|Física Teorica de la Materia Condensada, UAM, 28049 Madrid, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Silva Fernández
authors.affiliation: Laboratoire Kastler Brossel, UPMC-Paris 6, ÉNS et CNRS, 75005 Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Bramati
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.|Università del Salento, Dipartimento di Matematica e Fisica "Ennio de Giorgi", Via Arnesano, 73100 Lecce, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Gigli
authors.affiliation: Spin Optics Laboratory, Saint Petersburg State University, 198504 St Petersburg, Russia.|CNR-SPIN, Tor Vergata, viale del Politecnico 1, 00133 Rome, Italy.|Physics and Astronomy, University of Southampton, Highfield, Southampton SO171BJ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Kavokin
authors.affiliation: Física Teorica de la Materia Condensada, UAM, 28049 Madrid, Spain.|Russian Quantum Center, Moscow Region, 143025 Skolkovo, Russia.
authors.forename: F
authors.initials: F
authors.lastname: Laussy
authors.affiliation: CNR NANOTEC-Istituto di Nanotecnologia, Via Monteroni, 73100 Lecce, Italy.
authors.forename: D
authors.identifier: http://orcid.org/0000-0002-3831-8829
authors.initials: D
authors.lastname: Sanvitto