túlfolyadékosság

Túlfolyadékosság, also known as superfluidity, is a state of matter that exhibits zero viscosity. This means that a superfluid can flow indefinitely without losing energy. When a fluid enters a superfluid state, it can exhibit peculiar behaviors such as creeping up the walls of its container and flowing through extremely narrow channels, even against gravity. This phenomenon is typically observed at very low temperatures, approaching absolute zero.

The most well-known superfluids are helium-4 and helium-3 isotopes when cooled to extremely low temperatures. Helium-4 becomes superfluid at temperatures below 2.17 Kelvin (the lambda point), while helium-3 requires even lower temperatures, around 0.002 Kelvin. The transition to superfluidity is a phase transition, similar to how water freezes into ice.

The theoretical explanation for superfluidity involves quantum mechanics. At these extremely low temperatures, the particles in the fluid behave as a single quantum entity, described by a macroscopic quantum wave function. This collective behavior allows the fluid to flow without friction. Other phenomena associated with superfluidity include the "fountain effect" and the creation of quantized vortices. Superfluidity has important applications in scientific research, particularly in the study of quantum mechanics and condensed matter physics, and in technologies like sensitive gyroscopes and cryogenics.