Approximate quantum cellular automata and approximate algebras

Name: Approximate quantum cellular automata and approximate algebras
Start: 2026-11-05T10:15:00+00:00
End: 2026-11-05T11:00:00+00:00
Location: Seminar Room 1, Newton Institute

Hosted by Isaac Newton Institute Seminar Series

Thursday 5 November 2026, 10:15

Venue time (London)

Seminar Room 1, Newton Institute

Thursday 5 November 2026, 10:15Venue time (London)

Thursday 5 November 202610:15 · Venue time (London)

Seminar Room 1, Newton Institute

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Speaker: Michael Walter (Ludwig-Maximilians-Universität München)
Series: Isaac Newton Institute Seminar Series
Note: MMBW03 - Structure of entanglement

Quantum cellular automata (QCAs) describe quantum dynamics with strict light cones, while local Hamiltonian evolution generally has small tails. Can dynamics with approximate light cones exhibit genuinely new behavior, or is it always close to an exact QCA? We will show that every such dynamics can be rounded in one dimension, including on finite rings, and discuss the consequences for the classification of quantum information flow. Previous work used global methods that do not apply here. Our approach is local and also applies to dynamics specified only on patches. A key ingredient is a new rigidity theorem for approximate algebras of observables. Based on joint work with Daniel Ranard and Freek Witteveen (arXiv:2603.08702 and subsequent developments).