Researchers at the University of Basel and the Technical University of Munich have developed a new method to reveal the collective motion of electrons in one of the most elusive states of matter: the Wigner crystal. Using light, the physicists were able to uncover previously inaccessible properties of this fragile quantum state.

When electrons confined to a two-dimensional plane interact strongly with one another, they can stop moving independently and instead form a periodic lattice resembling the atomic arrangement in an ordinary crystal.

This ordered state, known as a Wigner crystal, has fascinated scientists for decades because its order does not arise from the internal structure of the host material, but from interactions among the electrons themselves.