Berlin 2018 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 6: Dynamics in many-body systems: interference, equilibration and localization I (joint session DY/TT)

DY 6.5: Vortrag

Montag, 12. März 2018, 11:00–11:15, EB 107

Construction of exact constants of motion and effective models for many-body localized systems — •Marcel Goihl, Marek Gluza, Christian Krumnow, and Jens Eisert — Dahlem Center for Complex Quantum Systems, Freie Universitat Berlin, 14195 Berlin, Germany

One of the defining features of many-body localization is the presence of extensively many quasi-local conserved quantities. These constants of motion constitute a corner-stone to an intuitive understanding of much of the phenomenology of many-body localized systems arising from effective Hamiltonians. They may be seen as local magnetization operators smeared out by a quasi-local unitary. However, to accurately identify such constants of motion remains a challenging problem. Current numerical constructions often capture the conserved operators only approximately or trade desirable properties such as exactly commuting with the Hamiltonian against each other, restricting a conclusive understanding of many-body localization. In this talk, we use methods from the theory of quantum many-body systems out of equilibrium to establish a new approach for finding a complete set of exact constants of motion which are in addition by construction guaranteed to represent Pauli-z operators. By this we are for the first time able to construct and investigate the proposed effective Hamiltonian using exact diagonalization. Hence, our work provides an important tool expected to further boost inquiries into the breakdown of transport due to quenched disorder.