SQUAT

Quantum emitters such as atoms or molecules are at the forefront of fundamental physics tests, metrology and quantum technology. The growing need for miniaturization puts atoms and molecules in close proximity to solid-state surfaces leading to hybridization. Solid-state platforms modify the vacuum fluctuations of the electromagnetic field, inevitably changing the quantum emitter's internal structure such as energy levels, radiative lifetimes, and symmetry properties. Conversely, structuring the environment around atoms and molecules in a controlled fashion provides a unique way to shape the electromagnetic fluctuations and tune the properties of quantum systems. The project aims to explore the interaction of an atom or molecule with the vacuum, tailored and colored by thermally excited surface modes of macroscopic bodies. It combines one theory group of experts in atom and molecule-surface interactions, from the University of Rostock in Germany, with an experimental group from the University of Paris 13, specialists in near-field atom and molecule-surface interactions in vapour cells. Thermal vapour cells containing atoms or molecules are compact platforms that interface atoms and molecules with solid-state devices for the purposes of quantum physics experiments and quantum technologies. Fabricating this new generation of quantum devices requires inevitably fundamental knowledge of the interaction of atoms and molecules with planar and nanostructured surfaces. We will pursue the following objectives: 1) We will probe the interaction of Rydberg atoms with dielectric surfaces demonstrating multipole interactions beyond the usual dipole-dipole interaction approximation, 2) We will probe the molecule-surface interaction with transmission spectroscopy inside molecular gas nanocells and we will investigate the effects of molecular orientation with respect to the surface (anisotropy of molecule-surface interactions), 3) We will fabricate a new generation of vapour cells with nanostructured windows (planar metamaterials) for tailoring the atom (molecule)-surface interaction. 4) We will spectroscopically probe the interaction of Rydberg atoms in nanostructured cells, coupled with terahertz resonators and demonstrate tuning of the Rydberg surface interaction. The proposal's main strength results from a close collaboration between theory and experiment. Ultimately, the knowledge gained will allow us to shape the quantum vacuum around atoms and molecules. Although the studies of atom and molecule surface interactions lie in the field of fundamental quantum physics they could have implications to quantum technologies, physical chemistry, astrophysics, fluid dynamics, and even biology.