Shaping the QUantum vacuum around AToms and molecules – 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.