Speaker
Description
An ensemble of atoms coupled to a common electromagnetic environment displays collective effects, such as sub- and superradiance. These can be harnessed experimentally in cold atom array experiments, where the atoms are tightly confined and close to the motional ground state. This requires to treat atomic motion, both quantum and thermally induced, as a quantum degree of freedom which couples to the internal degrees of freedom of the atoms. Here, we develop a theoretical framework to describe two-dimensional quantized motion in subwavelength atomic arrays within the Lamb-Dicke limit. We derive the Lindblad master equation for a 1D chain of atoms as well as 2D square and ring lattices, demonstrating that this formalism can be readily applied to multiple geometries. In 1D, we show that thermally induced motion results in a change of the exponential decay laws, even for temperatures approaching zero. In 2D, we also study how quantized motion affects the reflectance of an atomic optical mirror, revealing a general dependance on the reduced interatomic distance, dipole moment orientation and detuning. The quantized motion results in a decreased reflectance, while preserving the collective character of the response, as visible from the width of the reflectance spectra and collective Lamb Shift.
