Applications of Scrooge randomness

Determine whether Scrooge randomness generated naturally by deep thermalization and Hilbert-space ergodicity enables applications in quantum information science that cannot be achieved with Haar-randomness.

Background

Haar randomness is already useful for benchmarking, state learning, certification, and related quantum-information protocols, whereas Scrooge ensembles arise naturally under constraints such as finite temperature or conserved quantities. Because Scrooge randomness is more difficult to implement on digital hardware, its practical value remains less established.

The authors identify as unresolved whether the distinctive information-minimizing structure of Scrooge ensembles can provide capabilities beyond those available from Haar-random ensembles.

References

As this program continues to develop, an outstanding question is whether Scrooge randomness---which emerges organically from deep thermalization and HSE, but is more challenging to implement on digital hardware---could unlock unique applications beyond Haar-randomness.

— Deep thermalization and Hilbert space ergodicity  (2609.30248 - Mark et al., 24 Sep 2026) in Discussion and outlook, subsection “Applications”