Prof. Dr. Daniele Fausti (U Erlangen-Nuremberg, U Trieste, Elettra): Quantum spectroscopies for quantum materials

The rich phase diagrams of many complex quantum materials (CQM) is the result of the intricate interplay between electrons, phonons, and magnons. This makes CQMs very susceptible to external parameters such as pressure, doping, magnetic field, and temperature that can in turn be used to finely tune their properties. The same susceptibility makes them the ideal playground to design experiments where the interaction between tailored electromagnetic fields and matter can trigger the onset of new, sometimes exotic, physical properties and disclose a new regime of physics where thermodynamic limits may be bridged and quantum effects can, in principle, appear at ambient conditions.
In this presentation, I will review briefly our results in archetypal strongly correlated cuprate superconductors which demonstrate the feasibility of a light-based control of quantum phases in real materials. I will then introduce our new approaches to time domain spectroscopy going beyond mean photon number observables and show that the statistical features of light can provide information on time dependent fluctuations and interactions, underling materials' functionalities, which are not visible in standard linear and non-linear optical spectroscopies.
Finally, I will elaborate on how the control of time dependent fluctuations in strong light-matter coupling can be used to control the functionalities in CQM, describe the platform we recently developed to embed solid state samples into resonant optical cavities, and show how the hybridization of light and matter can be used to control the metal-insulator transition temperature in 1T-TaS2.