Atoms settled along a chain of traps, like a line of coastal forts. Nearby, a quantum sea: a Bose-Einstein condensate (a substance with zero resistance, where particles move as a single wave). Laser pulses excite the atoms, which then release energy into the sea, obeying quantum laws. It would seem that such an exchange would empty everything. But the opposite happens: after many cycles, all the forts are empty except the two at the ends. The inner ones have fallen, the boundary ones stand unshaken.

The reason is a directed flow of disorder outward: the system loses energy in such a way that stability is preserved only at the edges. Precise calculations and computer simulations agree on one thing: only the boundaries are stable, no matter how many atoms there were initially. Most surprisingly: the laser, usually associated with chaos, here acted as an instrument of strict selection, ruthlessly clearing out the middle. Now such edge states are seen as natural cells for quantum memory — information writes itself onto the periphery.