An Italian-Canadian team has done even better. Researchers at the CNR Nanotec in Lecce, Italy, in collaboration with the team of the Ecole polytechnique de Montréal (Canada), obtained at room temperature, superfluid light, which not only flows like a liquid, but without any turbulence, marrying the contours of the least obstacle.
Liquid light? However, did not Einstein demonstrate at the beginning of the 20th century that light was a flow of particles: photons moving in a straight line? And did he not explain that these photons, stubbornly refusing to interact with each other, behaved like a perfect gas? Nothing in common with water, whose liquid properties result instead from multiple inter actions between molecules. By adjusting the formulas of physics, new particles of light appeared.
In 1958, the American John Hopfield and the Soviet Vladimir Agranovich, to circulate light in semiconductor materials. Their equations were formal: by adjusting the parameters, the photons would have to bind to excitation states of matter called excitons to form hybrid quasi-particles: polaritons.
"Just as the hydrogen atom associates a nucleus and an electron, the polariton is a composite system that associates a photon and an exciton, but these polaritons carried with them a great promise: that of strongly interacting with each other. other" according to Quentin Glorieux, a researcher at the Kastler Brossel laboratory at the Pierre and Marie Curie University in Paris.
These experiments will be published today in the June 5 issue of Nature Physics and are the result of work done at the Advanced Photonics Laboratories of the Italian National Research Council's Institute for Nanotechnology in Lecce, in collaboration with Polytechnique Montréal, the Aalto University Center of Excellence in Finland and Imperial College London.
Full article : https://phys.org/news/2017-06-stream-superfluid.html
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