Gabriel Dutier

We present a method utilizing atomic diffraction patterns and statistical analysis tools to infer the Casimir-Polder interaction between argon atoms and a silicon nitride nanograting. The quantum model that supports the data is investigated in detail, as are the roles of nanograting geometry, finite-size effects, slit width opening angles, Lennard-Jones potentials, and patch potentials. Our findings indicate that the atom-surface potential strength parameter is C 3 = 6.9 ± 1.2 meV nm 3 . This value is primarily constrained by the knowledge of the nanograting geometry. The high sensitivity of our method paves the way for precise determination of the Casimir-Polder potential and exploration of new short-distance forces.

At nanometer separation, the dominant interaction between an atom and a material surface is the fluctuation-induced Casimir–Polder potential. We demonstrate that slow atoms crossing a silicon nitride transmission nanograting are a remarkably sensitive probe for that potential. A 15% difference between nonretarded (van der Waals) and retarded Casimir–Polder potentials is discernible at distances smaller than 51 nm. We discuss the relative influence of various theoretical and experimental parameters on the potential in detail. Our work paves the way to high-precision measurement of the Casimir–Polder potential as a prerequisite for understanding fundamental physics and its relevance to applications in quantum-enhanced sensing.

A pulsed beam of metastable argon atoms having a low tunable velocity (10 to 150 m s⁻¹) is produced with a very substantial brightness (9 × 10⁸Ar* s⁻¹ sr⁻¹). The present original experimental configuration leads to a variable velocity dispersion that can be smaller than the standard Brownian one. This behaviour, analysed using Monte Carlo simulations, exhibits momentum stretching (heating) or narrowing (cooling) entirely due to a subtle combination of Doppler and Zeeman effects.

This paper presents our current measurements in a vapor nanocell aiming at a test of the distance-dependence of the atom-surface interaction, when simple asymptotic descriptions may turn to be not valid. A state-of-the-art of atom-surface interaction measurements is provided as an introduction, along with the comparison with the theory of the van der Waals (or Casimir-Polder) interaction; it is followed by a presentation of the most salient features of nanocell spectroscopy.