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 COVID19, all seminars are
**canceled** beginning Thursday March 12th until further notice
Topological insulators are exotic phases that go beyond the GinzburgLandau
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