



02031nas a2200145   4500008004100000245007100041210006900112260001400181490000800195520154100203100002801744700002701772700001601799856007001815       2020                        eng d00aNoncommuting conserved charges in quantum many-body thermalization0 aNoncommuting conserved charges in quantum manybody thermalizatio  c4/15/20200 v1013 a<p>In statistical mechanics, a small system exchanges conserved quantities&mdash;heat, particles, electric charge, etc.&mdash;with a bath. The small system thermalizes to the canonical ensemble or the grand canonical ensemble, etc., depending on the quantities. The conserved quantities are represented by operators usually assumed to commute with each other. This assumption was removed within quantum-information-theoretic (QI-theoretic) thermodynamics recently. The small system&#39;s long-time state was dubbed &ldquo;the non-Abelian thermal state (NATS).&rdquo; We propose an experimental protocol for observing a system thermalize to the NATS. We illustrate with a chain of spins, a subset of which forms the system of interest. The conserved quantities manifest as spin components. Heisenberg interactions push the conserved quantities between the system and the effective bath, the rest of the chain. We predict long-time expectation values, extending the NATS theory from abstract idealization to finite systems that thermalize with finite couplings for finite times. Numerical simulations support the analytics: The system thermalizes to near the NATS, rather than to the canonical prediction. Our proposal can be implemented with ultracold atoms, nitrogen-vacancy centers, trapped ions, quantum dots, and perhaps nuclear magnetic resonance. This work introduces noncommuting conserved quantities from QI-theoretic thermodynamics into quantum many-body physics: atomic, molecular, and optical physics and condensed matter.</p>1 aHalpern, Nicole, Yunger1 aBeverland, Michael, E.1 aKalev, Amir  uhttps://journals.aps.org/pre/abstract/10.1103/PhysRevE.101.042117