superfluid helium
Superfluid helium is a unique state of matter that occurs when helium is cooled to temperatures close to absolute zero, around 2.17 Kelvin. In this state, helium exhibits remarkable properties, such as flowing without viscosity, which means it can move through tiny openings and around obstacles without losing energy.
This phenomenon is a result of quantum mechanics, where the atoms in helium behave collectively rather than individually. Superfluid helium is often studied in laboratories and has applications in fields like cryogenics and quantum physics, helping scientists explore the fundamental principles of matter and energy.