At extremely low temperatures, helium transforms into a superfluid state, exhibiting extraordinary properties that distinguish it from ordinary fluids. These properties include zero viscosity, infinite thermal conductivity, and the ability to flow through narrow capillaries without resistance. Moreover, superfluid helium can exhibit quantum mechanical effects on macroscopic scales, making it an intriguing area of study for scientists working on complex experiments like the LHC.
The two primary isotopes of helium, helium-3 and helium-4, behave differently in their superfluid states. Helium-4 atoms are bosons with zero spin, allowing them to form a coherent quantum state at relatively higher temperatures. In contrast, helium-3 atoms are fermions that require much lower temperatures to form similar coherent states through electron pairing, analogous to superconductivity.
Superfluid helium’s unique properties make it an indispensable resource in several scientific fields, especially those requiring low temperatures and high precision. Some notable applications include cryogenics, where it is widely used as a cooling agent due to its exceptional thermal conductivity and ability to maintain extremely low temperatures. Major research facilities, such as the LHC, rely heavily on superfluid helium to cool down their massive magnets and detectors, enabling them to operate at optimal performance levels. Magnetic Resonance Imaging (MRI), where superconductive magnets, which require liquid helium to achieve and maintain superconductivity, are used to generate detailed images of internal body structures, revolutionizing medical diagnostics and treatment.