Events

Hadi Rammal presents

Numerical studies of electronic transport in novel quantum regimes

Monday, December 15th 2025 at 14:00

Seminar room – Building A – CNRS

The defence will be in English.

Abstract: This thesis demonstrates how slow quantum fluctuations in a material, often originating from atomic or molecular vibrations, can temporarily trap moving electrons —– a phenomenon called transient localization — by creating a dynamically disordered landscape. Using accurate numerical simulations, we find that the presence of these sluggish fluctuations can explain the observation of large electrical resistances as well as anomalous optical properties, two widespread phenomena that have long challenged our understanding of charge transport in quantum materials. We then proceed to generalize these results to other physical situations, building an archetypal model in which electronic carriers interact with quantum two-level systems, that are relevant to broad classes of disordered systems and strange metals. Using this model we address the question of how electrical conduction can emerge in disordered insulators at finite temperature, providing the first numerical proof (and critical reassessment) of variable-range hopping theory within an approximation-free Hamiltonian formulation. Overall, our results add to the growing evidence that quantum effects beyond widely accepted semiclassical theories govern charge transport in many quantum materials of interest.