A room-temperature "supercurrent" has been identified in a Bose–Einstein condensate of quasiparticles called magnons. That's the finding of an international team of researchers, which says the work opens the door to using magnons in information processing. Other researchers, however, believe the claim is premature, arguing that less-novel explanations have not been ruled out.
Ref: Supercurrent in a room-temperature Bose–Einstein magnon condensate. Nature Physics (1 August 2016) | DOI: 10.1038/nphys3838
A supercurrent is a macroscopic effect of a phase-induced collective motion of a quantum condensate. So far, experimentally observed supercurrent phenomena such as superconductivity and superfluidity have been restricted to cryogenic temperatures. Here, we report on the discovery of a supercurrent in a Bose–Einstein magnon condensate prepared in a room-temperature ferrimagnetic film. The magnon condensate is formed in a parametrically pumped magnon gas and is subject to a thermal gradient created by local laser heating of the film. The appearance of the supercurrent, which is driven by a thermally induced phase shift in the condensate wavefunction, is evidenced by analysis of the temporal evolution of the magnon density measured by means of Brillouin light scattering spectroscopy. Our findings offer opportunities for the investigation of room-temperature macroscopic quantum phenomena and their potential applications at ambient conditions.