Atomic spins set quantum fluid in motion: Experimental realization of the Einstein–de Haas effect

The Einstein–de Haas effect, which links the spin of electrons to macroscopic rotation, has now been demonstrated in a quantum fluid by researchers at Science Tokyo. The team observed this effect in a Bose–Einstein condensate of europium atoms, showing that a change in magnetization causes the coherent transfer of angular momentum from atomic spins to fluid motion, thereby experimentally demonstrating that angular momentum is conserved at the quantum level.