Fan Wu

Imagine a stack of pancakes where each pancake is magnetized, but the magnetization directions in adjacent pancakes are opposite. That's exactly how this new magnetic material is arranged: in each atomic layer, all magnetic moments — the atom's 'arrows'—point in one direction, while the next layer is magnetized in the opposite direction.

Atoms have been caught in a ring of light. This is not a metaphor: laser beams form a ring-shaped trap in which atoms move in circles. The light not only holds them but also couples the atom's rotation to its internal 'compass'—the spin. As a result, an atom running around the ring senses which way it's going, and this changes its internal state. This coupling is not just elegant.