Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DY: Fachverband Dynamik und Statistische Physik
DY 2: Nonequilibrium Quantum Systems (joint session TT/DY)
DY 2.9: Vortrag
Montag, 17. März 2025, 11:45–12:00, H31
Tuning of slow dynamics in quantum East Hamiltonians motivated by Graph theory — •Heiko Georg Menzler1, Mari Carmen Bañuls2,3, and Fabian Heidrich-Meisner1 — 1Institut für Theoretische Physik, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany — 2Max-Planck-Institut für Quantenoptik, D-85748 Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), Schelling Strasse 4, D-80799 München
In-between fully ergodic/localized quantum system there exist many systems with atypical relaxation behaviors. One of these systems is the quantum East (QE) model. The classical East model is a central, exemplary model for glassy dynamics and kinetic constraints. Also its quantum counterpart features slow dynamics without conservation laws or disorder. However, the presence of slow dynamics has not yet been fully understood from a quantum perspective. Introducing an interpretation of constrained dynamics based on graph theory, we theoretically demonstrate control over the slow dynamics of QE models. As a general hypothesis, we propose that strong hierarchies between nodes on the Fock space graph are related to the presence of slow dynamics. To quantify hierarchical structures, we develop a measure of centrality for generic Hamiltonian matrices, reminiscent of established centrality measures from graph theory. Based on these ideas, we show how we can introduce detuning to alter the hierarchical structure in the QE model and acutely change the resulting constrained dynamics, evidenced by eigenstate structure in the detuned QE models.
Supported by DFG, German Research Foundation via FOR 5522
Keywords: slow dynamics; ergodicity; constrained dynamics; graph theory; quantum glasses