The Fermion-Rotor Model
- đ¤ Speaker: David Tong (University of Cambridge)
- đ Date & Time: Monday 29 September 2025, 10:00 - 11:30
- đ Venue: Seminar Room 2, Newton Institute
Abstract
Many years ago, Joe Polchinski wrote down a simple impurity model describing chiral fermions in d=2 dimensions interacting with a localised rotor degree of freedom at the origin. The model is deceptive in its simplicity. A quantum anomaly means that ingoing fermions carry different quantum numbers from outgoing fermions and naively it appears that no consistent scattering is possible. This mimics a problem that occurs when fermions in the Standard Model scatter off monopoles. Joe was unable to solve his model but recently others made progress. I’ll explain the model, its solution, and its relation to boundary states and twist operators.
Series This talk is part of the Isaac Newton Institute Seminar Series series.
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David Tong (University of Cambridge)
Monday 29 September 2025, 10:00-11:30