Deutsch Intern
Fakultät für Physik und Astronomie

Würzburg Seminar on Quantum Field Theory and Gravity

Non-Abelian symmetry can increase entanglement entropy
Date: 02/07/2023, 2:15 PM - 3:15 PM
Organizer: Lehrstuhl für Theoretische Physik III
Speaker: Shayan Majidy

The pillars of quantum theory include entanglement and operators' failure to commute. The Page curve quantifies the bipartite entanglement of a many-body system in a random pure state. This entanglement is known to decrease if one constrains extensive observables that commute with each other (Abelian ``charges''). Non-Abelian charges, which fail to commute with each other, are of current interest in quantum information and thermodynamics. For example, noncommuting charges were shown to reduce entropy-production rates and conflict with the eigenstate thermalization hypothesis. We quantify the effects of a symmetry's non-Abelian nature--of charges' noncommutation--on Page curves. First, we construct two models that are closely analogous but differ in whether their charges commute. We show analytically and numerically that the noncommuting-charge case has more entanglement. Hence charges' noncommutation can promote entanglement. This result demonstrates a relationship between non-abelian symmetries and entanglement.

Ref: Shayan Majidy, Aleks Lasek, David Huse, and Nicole Yunger Halpern "Non-Abelian symmetry can increase entanglement entropy." Physical Review B 107.4 (2023): 045102.