In highly excited bulk superfluid, many vortex lines interact with each other forming quantum turbulent states.
[2] In general, 2D quantum turbulence (2DQT) can exhibit complex phenomenology involving coupled vortices and sound in compressible superfluids.
At leading order a quantum vortex is massless, with each filament moving with the net background flow and obeying a form of the Biot–Savart law.
[22][23] In strongly non-equilibrium quantum fluid dynamics, clustered states can develop as a result of steady inverse energy cascade from small scale forcing, leading to an accumulation of energy at the system scale in the form of macroscopic flow due to vortex charge ordering.
2DQT regime has been established in ultracold gases,[24] superfluid helium,[25] and in exciton-polariton condensates comprising quantum fluids of light.