The research group led by Oriol Romero-Isart studies topics in the fields of theoretical quantum optics and quantum nanophysics in the context of quantum science and technology. One of the main research interests is the observation of quantum phenomena with levitated micrometer-sized particles. Such systems push the boundary of quantum physics into uncharted territory, where the very validity of quantum physics and its interplay with gravity could be put to the test. Achieving this goal requires a fundamental understanding of the internal physics of levitated nanoparticles as well as their interaction with electromagnetic fields. The group is also interested in nano-optics, including topics such as the tailoring of spatio-temporal features of the electromagnetic field, light-matter interaction at the nanoscale, and out-of-equilibrium quantum electrodynamics. The group proposes cutting-edge experiments and develops the underlying theory while closely collaborating with experimental groups.