Séminaires : Phd Seminar - Séminaire des doctorant.e.s

Le séminaire des doctorant.e.s est l'occasion pour les doctorant.e.s de présenter des résultats et des problématiques dignes d'intérêt devant un public de non-spécialistes. L'ambiance y est informelle ; poser des questions naïves est encouragé, et les questions moins naïves sont bienvenues dans la mesure où elles n'entravent pas le bon déroulement de l'exposé.

Chaque jeudi à 18h, en alternance entre Jussieu et Sophie Germain.

The PhD seminar is an opportnuity for PhD students to present results and topics worthy of interest in front of a non-specialist audience. The mood is informal ; asking naive questions is highly encouraged and less naive questions are also welcomed, as long as they don't intefere with the smoothness of the talk.

Every Thursday at 6pm, alternating between Jussieu and Sophie Germain.

I will introduce the main objects from spectral theory of infinite dimensional operators: the domain, the resolvent and the spectrum. I will then describe an analytic family of non normal operator \(D(\alpha)\) for \(\alpha \in \mathbb C\) such that \(\alpha\mapsto \mathrm{Spec}(D(\alpha))\) is discontinuous. The points of discontinuity are called "magic angles" and I will show that there are infinitely many of them. This is joint work with Simon Becker and Maciej Zworski.

The existence of these angles were predicted by Bistritzer–MacDonald in 2011 and were observed experimentally in 2018. They correspond to specific "twisting angles" between two sheets of graphene for which we observe supraconductivity.