PhD Position Terahertz Cavity Electrodynamics of Superconducting Collective Modes, Ecole Polytechnique, Paris, France

Light control of a material’s properties is an emerging field with potentially far-reaching applications. Within this field enhancing or modifying superconductivity (SC) holds a special place ever since the discovery of a superconducting-like state in several materials well above their equilibrium SC temperature. The dynamics of superconductors driven out-of-equilibrium is governed by their collective mode spectrum, and in particular the SC amplitude mode which is an analog of the Higgs
mode in high-energy physics. These SC collective modes not only give fingerprints of the nature of the ground state, but also a path to dynamically drive or even control SC order. Light control of SC may be achieved through two main routes. The first involves driving the collective modes with light pulses tuned to their energy, typically in the THz frequency range, which may dynamically modify SC properties such as the pairing potential and explore new regions of the free energy landscape inaccessible via static means. The second route involves dressing the SC collective modes with vacuum fluctuations through strong light-matter coupling in THz cavities aiming to harness hybrid light-matter states to engineer novel equilibrium phases of matter without external driving.