👉 The Leon fluid, named after the physicist Leon Brillouin, is a theoretical model used to describe the dynamics of superfluid helium-4 at extremely low temperatures, specifically below 2.17 Kelvin (the lambda point). This fluid exhibits unique properties such as zero viscosity and the ability to flow without dissipating energy, allowing it to climb walls and form persistent currents. The Leon fluid theory incorporates quantum mechanical effects that distinguish superfluidity from classical fluid behavior, providing insights into phenomena like quantized vortices and the frictionless flow of superfluids. It is a crucial framework for understanding the macroscopic quantum behavior observed in these exotic states of matter.