Photon fluid
Researchers have reported an optical experiment that characterises the physics of a ‘’photon fluid’’ in a medium with a nonlocal thermal-induced nonlinearity. The measurements highlight a sonic dispersionless propagation of collective excitations of the photon fluid, a signature of a superfluid behaviour. This work opens new opportunities for performing related experiments that will involve the study of the transition from laminar flow at subsonic speeds to turbulent dissipative flow at supersonic speeds.