Emergent quantum state designs and biunitarity in dual-unitary circuit dynamics

Understand

Recent works have investigated the emergence of a new kind of random matrix behaviour in unitary dynamics following a quantum quench.

• Starting from a time-evolved state, an ensemble of pure states supported on a small subsystem can be generated by performing projective measurements on the remainder of the system, leading to a projected ensemble.
• In chaotic quantum systems it was conjectured that such projected ensembles become indistinguishable from the uniform Haar-random ensemble and lead to a quantum state design.
• Exact results were recently presented by Ho and Choi [Phys.