Xiaohui Song

In 1963, a Tanzanian schoolboy named Erasto Mpemba noticed that hot ice cream freezes faster than cold. That paradox, named after him, long remained a subject of debate in classical thermodynamics. Now the quantum world offers its own version: a state with more strongly broken symmetry can recover it faster than a less broken one.

All matter, from stars to humans, is built from particles that in the Standard Model are divided into two families. But there's a third, rare kind — particles that, when swapped, don't just exchange places but tie themselves into a knot, remembering the intertwining rather than the path.

Quantum dots are tiny traps for electrons, about the size of an atom, but artificially made. They can store and process information, like miniature cells of a future computer. Usually, to change the state of such a dot, you need to run a wire to it and apply a voltage. But in the new work, scientists showed that this can be done without direct contact — simply by acting on a neighboring dot.