Quantum physics

• This lecture aims at the description of the interaction between quantum matter in its simplest form, an atom, and an electromagnetic field. A semi-classical approach, where the field is classical, is first considered, including relaxation of the atom. We then study the quantization of the electromagnetic field and its relaxation, before its interaction with an atom is described in a full quantum model.

Recent years have seen enormous experimental progress in preparing, controlling and probing quantum systems in various regimes far from thermal equilibrium. Examples include systems as ultra-cold atomic quantum gases under time-dependent perturbations, driven non-linear cavity QED systems or strongly correlated electrons in solid-state materials under ultra-fast optical excitations.

The main goal of this course is to provide an advanced view of the optical response of quantum materials. 

Since the 80’s, laser cooling has enabled the production of sub-milliKelvin dilute atomic gases - which can be further cooled to the nanoKelvin regime.