Youssef Aziz Alaoui

In the quantum world, there are rules that seem to be broken. One of them is the conservation law: if in classical physics symmetry guarantees the conservation of charge, then in the quantum description this guarantee can disappear. This phenomenon is called a quantum anomaly.

Molecules in an ultracold gas are like tiny magnets: they attract when far apart, but when they get close they can stick together for good. Such sticking destroys the gas: particles drop out of the game, and you never reach the quantum regime where all of them behave as one.