Superfluid motion and drag-force cancellation in a fluid of light

Abstract

Quantum fluids of light merge many-body physics and nonlinear optics, revealing quantum hydrodynamic features of light when it propagates in nonlinear media. One of the most outstanding evidence of light behaving as an interacting fluid is its ability to carry itself as a superfluid. Here, we report a direct experimental detection of the transition to superfluidity in the flow of a fluid of light past an obstacle in a bulk nonlinear crystal. In this cavityless all-optical system, we extract a direct optical analog of the drag force exerted by the fluid of light and measure the associated displacement of the obstacle. Both quantities drop to zero in the superfluid regime characterized by a suppression of long-range radiation from the obstacle. The experimental capability to shape both the flow and the potential landscape paves the way for simulation of quantum transport in complex systems.

Wave condensation with weak disorder versus beam self-cleaning in multimode fibers

“…Extension of the theory to consider other forms of nonlinear effects would also be interesting, such as saturable or nonlocal nonlinearities in relation with atomic vapors beam cleaning experiments [108]. In addition, there is a growing interest for experimental demonstrations of superfluid light flows in bulk materials [109][110][111]. The experiments of condensation in MMFs would allow to study the nucleation of superfluid vortices induced by a rotating confining potential (along the 'time' z−variable) in manufactured multimode fibers, in analogy with rotating trapped BECs [1].…”

Wave breaking and formation of dispersive shock waves in a defocusing nonlinear optical material

“…In many instances one can actually simplify the above expressions (26) and (31): for reasonable values of c m (chosen to be of same order as c 0 in our simulations) the elliptic integral K(m) turns out to be approximately equal to π/2 for all points P in the three regions. In this case, the exact expressions (26) and (31) can be replaced by a simple approximation χ(P ) χ app (P ) which reads, when P is in region n = 1 or 3:…”

Starting Flow Past an Airfoil and its Acquired Lift in a Superfluid

“…Accelerated hydrofoils and wings have recently been used to create vortices of arbitrary shape in classical fluids [26,27], a technique which might generalize to superfluids, offering a potentially powerful new procedure in superfluid manipulation, vortex generation, and observation of quantized lift -a measurement originally attempted in 4 He by Craig & Pellam [28] to demonstrate the quantization of circulation, later detected by Vinen using a different setup [29]. Among the various superfluid experimental realizations, some have recently started to address questions on vortex nucleation and manipulation using moving obstacles including cold atomic gases [21,23,[30][31][32][33] and quantum fluids of light [34,35]. Details of each experimental realization will differ: 3d effects need to be considered for non quasi-two-dimensional BECs, the rotons' emission instead of vortex shedding might be important in 4 He, and out-ofequilibrium exciton-polariton systems will require modelling to consider intrinsic forcing and damping terms.…”