There has been a series of very important advancements on the role of Fermi surface topological transitions in correlated systems in the last few years. The effects of the usual Lifshitz transitions or more complicated Fermi surface topological transitions and the associated van Hove singularities in correlated systems such as heavy fermions, twisted bilayer graphene, iron pnictides, ferromagnetic superconductors, cobaltates, strontium ruthenates etc have been clearly observed. Long-standing experimental puzzles have been understood in the framework of higher order Fermi surface topological transitions. At the same time there is theoretical progress on this front regarding classification of higher order van Hove singularities, effects of interactions and predictions of new effects. Quite recently there have been several reports of new materials that exhibit unusual physics as a result of van Hove singularities: Bernal type bilayer graphene, kagome’ superconductor CsV₃Sb_5.

This field is growing and the experimental interest is rather high as many unresolved puzzles can be attributed to this kind of topological transitions. New materials will definitely appear.

The aim of the proposed mini-colloquium is to bring together all the researchers interested in those developments.

Invited speakers:

• Prof. Peter Wahl, University of St Andrews
• Prof. Titus Neupert, University of Zurich
  
• Prof. Alexandre Pourret, University of Grenoble Apls