CANCELED - Detection of the topological invariants in cold atom and photonic experiments.

DIPC Seminars

Speaker

CANCELED - Alexandre Dauphin, ICFO, Barcelona, Spain

When

2020/03/18
13:00

Place

Donostia International Physics Center

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In an effort to limit the current spread of COVID-19, all seminars are **canceled** beginning Thursday March 12th until further notice Topological insulators are exotic phases that go beyond the Ginzburg-Landau theory of phase transitions: instead of being characterized by a local order parameter, they are classified by a global order parameter called the topological invariant. The latter makes them very robust against local perturbations. An example of such phases is the quantum Hall effect, where the quantification of the transverse conductivity directly reflects the topological invariant of the system. Topological insulators can also be simulated with quantum simulators. These versatile platforms allow one to engineer the desired Hamiltonian in a controllable environment and to reach a regime of parameters hardly accessible in solid state experiments. In the first part of the talk, I will discuss the realization of the disordered SSH model in a cold atom experiment. We probed the robustness of the topology with respect to disorder through the measurement of a bulk observable, the mean chiral displacement. We also observed the topological Anderson insulator, where the disorder drives an initially trivial insulator into a topological insulator. In the second part of the talk, I will discuss the realization of a 2D Chern insulator in a 2D photonic quantum walk. We studied wave packets’ dynamics under the action o a constant force and measured the Chern numbers in both topologically trivial and non trivial regimes. Host: Ricardo Diez Muino