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SYAD: Symposium SAMOP Dissertation-Prize 2018

SYAD 1: SAMOP Dissertation-Prize

SYAD 1.3: Hauptvortrag

Dienstag, 6. März 2018, 11:30–12:00, B Audimax

Engineering and probing topological bands with ultracold atoms — •Nick Fläschner — Institut für Laserphysik, Universität Hamburg

Topological matter such as quantum Hall systems or Chern insulators and their fascinating properties have become a major research focus of modern physics. Key for the description and understanding of topological matter are topological indices like Chern numbers and geometrical properties such as the distribution of Berry curvature. In this talk, I will present experiments demonstrating the capability of ultracold atoms for engineering and characterizing topological systems. By circularly shaking a hexagonal optical lattice, we realize a Haldane-like Floquet Hamiltonian featuring topologically non-trivial bands. After an adiabatic preparation of the Floquet ground state, we demonstrate a novel momentum-resolved state tomography and achieve the first measurement of Berry curvature in a lattice system. Furthermore, we use the exquisite control of our system to realize various quenches in the topological phase diagram and observe the dynamical evolution of the highly-excited system. Surprisingly, we observe topological features in the time-dependent wave function which allow directly measuring the Chern number of the ground state. Our measurements not only allow mapping out the topological phase diagram but also establish a novel approach on characterizing topological systems, which might also be fruitful for studying interacting topological phases.