Superfluids are an exotic state of matter in which particles flow without experiencing viscosity. Hiroki Ikegami and colleagues from the RIKEN Low Temperature Physics Laboratory in Wako have now observed another remarkable property of superfluids—the breaking of a fundamental natural symmetry in superfluid helium-3 (3He). The finding is important for many areas of physics, says Ikegami. "Spontaneous symmetry breaking is a universal and fundamental concept found in various branches of physics. It describes that nature prefers taking a less symmetric state even if underlying laws are symmetric."
