Exact Results in Quantum Theory
sala 1.40, ul. Pasteura 5
2026-01-16 (14:15) 
Mathieu Lewin (Universite Paris-Dauphine)
Counterexample to the convexity of the energy of quantum electrons in atoms and molecules
Experimental data suggest that the minimal energy of an atom or molecule is always convex in the number of electrons. We give the first counterexample to this conjecture, for a molecule containing nuclei with small fractional charges. The conjecture is still open in the physical case of integer charges. The argument is based on optimal transport methods. Joint work with Simone Di Marino (Genova) and Luca Nenna (Paris-Saclay).