Quantum Pseudorandom Scramblers

Understand

Quantum pseudorandom state generators (PRSGs) have stimulated exciting developments in recent years.

• A PRSG, on a fixed initial (e.g., all-zero) state, produces an output state that is computationally indistinguishable from a Haar random state.
• However, pseudorandomness of the output state is not guaranteed on other initial states.
• In fact, known PRSG constructions provably fail on some initial states.