Hydrodynamic nucleation of quantized vortex pairs in a polariton quantum fluid

• Published in: Nature physics Vol. 7; no. 8; pp. 635 - 641
• Main Authors: Nardin, Gaël, Grosso, Gabriele, Léger, Yoan, Piȩtka, Barbara, Morier-Genoud, François, Deveaud-Plédran, Benoît
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2011; Nature Publishing Group
• Subjects: Atomic; Classical and Continuum Physics; Complex Systems; Computational fluid dynamics; Condensed Matter Physics; Fluid flow; Fluid mechanics; Fluids; Helium; Mathematical and Computational Physics; Molecular; Nucleation; Optical and Plasma Physics; Physics; Physics and Astronomy; Polaritons; Quantum physics; Superfluidity; Theoretical; Turbulence; Turbulent flow; Velocity; Vortices
• ISSN: 1745-2473; 1745-2481
• DOI: 10.1038/nphys1959

Quantized vortices appear in quantum gases at the breakdown of superfluidity. In liquid helium and cold atomic gases, they have been indentified as the quantum counterpart of turbulence in classical fluids. In the solid state, composite light–matter bosons known as exciton polaritons have enabled studies of non-equilibrium quantum gases and superfluidity. However, there has been no experimental evidence of hydrodynamic nucleation of polariton vortices so far. Here we report the experimental study of a polariton fluid flowing past an obstacle and the observation of nucleation of quantized vortex pairs in the wake of the obstacle. We image the nucleation mechanism and track the motion of the vortices along the flow. The nucleation conditions are established in terms of local fluid density and velocity measured on the obstacle perimeter. The experimental results are successfully reproduced by numerical simulations based on the resolution of the Gross–Pitaevskii equation. Exciton-polariton fluids—which are composed of composite light–matter bosons—provide an experimental means for studying quantum fluids that are intrinsically out of equilibrium. These authors demonstrate the nucleation and dynamics of vortex–anti-vortex pairs in the flow of exciton-polaritons passing around an obstacle, and establish these systems as a platform for studying quantum turbulence.