Probing Topological Matter by «Heating»: From Quantized Circular Dichroism to Tensor Monopoles

Nathan Goldman
January 23rd, 2019 NATHAN GOLDMAN Université Libre de Bruxelles

The intimate connection between topology and quantum physics has been widely explored in solid-state physics, revealing a plethora of remarkable physical phenomena over the years. Building on their universal nature, topological properties are currently studied in an even broader context, ranging from ultracold atomic gases to photonics, where distinct observables and probes offer a novel view on topological quantum matter.

In this talk, I will discuss how the geometry of quantum states can be revealed using a universal scheme based on excitation-rate measurements upon periodic driving. When applied to Chern insulators or Landau levels, this approach leads to a quantized circular dichroism phenomenon, which can be interpreted as the dissipative counterpart of the quantum Hall effect. Besides, we will present protocols allowing for the experimental detection of the quantum metric tensor, which could be applied to detect new forms of monopoles in higher dimensions. Finally, I will report on the first experimental observation of quantized circular dichroism in an ultracold Fermi gas.

This activity is co-funded by the European Regional Development Funds (ERDF) allocated to the Programa operatiu FEDER de Catalunya 2014-2020, with the support of the Secretaria d’Universitats i Recerca of the Departament d’Empresa i Coneixement of the Generalitat de Catalunya for emerging technology clusters devoted to the valorization and transfer of research results (GraphCAT 001-P-001702).

Wednesday, January 23, 2019, 12:00. ICFO’s Seminar Room

Hosted by Prof. Maciej Lewenstein