Simulation of condensed gasses by variation of their coherent state expansions

Quantum mechanics has simple laws of motion, but it allows multiple worlds. Accounting for every possible world is hard work. To calculate quantum dynamics, we can randomly choose a world, calculate what happens, repeat, and average. This works when each world follows its own law of motion, but it fails in the really interesting case, where the motion of each world depends on what happens in the others. To do better, we can sample a several worlds, and calculate what happens when they interact in an approximately quantum way.