The piston Riemann problem in a photon superfluid

Abdelkrim Bendahmane (1) , Gang Xu (1) , Matteo Conforti (1) , Alexandre Kudlinski (1) , Arnaud Mussot (1) , Stefano Trillo (2)

1 PhLAM - Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523
2 Engineering Department [Ferrara]

Light flow in nonlinear media can exhibit quantum hydrodynamical features which are profoundly different from those of classical fluids. Here, we show that a rather extreme regime of quantum hydrodynamics can be accessed by exploring the piston problem (a paradigm in gas dynamics) for light, and its generalization, named after the celebrated mathematician Riemann, where the piston acts on a concomitant abrupt change of photon density. Our experiment reveals regimes featuring optical rarefaction (retracting piston) or shock (pushing piston) wave pairs, and most importantly the transition to a peculiar type of flow, occurring above a precise critical piston velocity, where the light shocks are smoothly interconnected by a large contrast, periodic, fully nonlinear wave. The transition to such extreme hydrodynamic state is generic for superfluids, but to date remained elusive to any other quantum fluid system. Our full-fibre setup used to observe this phenomenon in temporal domain proves to be a versatile alternative to other platforms currently employed to investigate the hydrodynamical properties of quantum fluids of light.

Domaines: Optique / photonique

Abdelkrim Bendahmane, Gang Xu, Matteo Conforti, Alexandre Kudlinski, Arnaud Mussot, et al.. The piston Riemann problem in a photon superfluid. Nature Communications, 2022. ⟨hal-03699262⟩