Trusted Entanglement

Schroedinger's cat is a a wild tiger! Describing the quantum state of as few as 1,000 quantum spins may require 2^1000 parameters — more than all the particles in the Universe! These exponentially complex quantum states are exactly what future quantum computers will be using to achieve impressive speed-ups over classical computations. Can we test whether complex quantum systems behave as they should, while trusting only our good old classical devices?