3 billion times colder than deep space

Physicists have used atoms about 3 billion times colder than interstellar space to open a portal to an unexplored realm of quantum magnetism by creating the universe's coldest fermions.

Physicists used lasers to cool fermions, atoms of Ytterbium, within about one-billionth of a degree of absolute zero, the unattainable temperature where all motion stops. They wanted to study the quantum properties of ultracold atoms.

Ytterbium atoms have six possible spin states, and physicists are the first to reveal magnetic correlations, which are impossible to calculate on a computer.