Physics: Superfluidity

Wikimedia Commons, CC BY-SA

Superfluidity Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy.

Commentary

Superfluidity Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. What is Superfluidity, and why does it matter? This concept appears everywhere in physics. Once you understand it, a wide range of natural phenomena start to make sense. Dee p dive: Superfluidity Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. When stirred, a superfluid forms vortices that continue to rotate indefinitely. Superfluidity occurs in two isotopes of helium (helium-3 and helium-4) when they are liquefied by cooling to cryogenic temperatures. It is also a property of various other exotic states of matter theorized to exist in astrophysics, high-energy physics, and theories of quantum gravity. The semi-phenomenological theory of superfluidity was developed by Soviet theoretical physicists Lev Landau and Isaak Khalatnikov. Superfluidity often co-occurs with Bose–Einstein condensation (BEC), but neither phenomenon is directly related to the other; not all Bose–Einstein condensates can be regarded as superfluids, and not all superfluids are Bose–Einstein condensates. Even when superfluidity and condensation co-occur, their magnitudes are not linked: at low temperature, liquid helium has a large superfluid fraction but a low condensate fraction; while a weakly interacting BEC, with almost unity condensate fraction, can display a vanishing superfluid fraction. Superfluids have some potential practical uses, such as dissolving substances in a quantum solvent.

Sources: Wikipedia