Superconductor Phase Transition Simulator

Condensed matter physics studies how huge numbers of interacting particles give rise to collective behaviour that no single particle shows on its own — superconductivity is the textbook example. This simulator renders a small crystal lattice as a grid of ions and lets you cool it through its critical temperature in real time. Above T_c, free electrons scatter randomly off the vibrating lattice, exactly like current through an ordinary resistive wire. Cross below T_c and the electrons condense into Cooper pairs that flow around the sample as a single persistent current with zero measured resistance. Push the applied magnetic field past the material's critical field while it is cold and watch the condensate quench back to a normal conductor — the same competition between temperature and field that limits every real superconducting magnet, from MRI scanners to fusion-reactor coils.