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Piégeage des états de Rydberg
Niveaux de Rydberg circulaires dans un champ électrique
We consider the case of Rydberg atoms in circular states. These have a large principal quantum number n, of the order of 50 in our discussion, along with maximal angular and magnetic quantum numbers (l=|m|=n-1). The atom therefore has both a large energy and a large angular momentum.
Principes du piège électrodynamique
As circular states are high-field seekers, they cannot be trapped by any configuration of d.c. electric fields, a maximum of the electric field modulus in vacuum being forbidden by Maxwell’s equations. It is however possible to trap if one uses a.c. potentials, as in the case of trapped ions.
Géometries étudiées, calculs des champs et potentiels
It is of course possible to design a geometry of electrodes which perfectly maps the desired hexapolar geometry [see the subfigure (a) in this page]. It requires two rings and two end caps. However, being closed in all three dimensions, such a geometry is hardly compatible with efficient atom loading, nor with the idea of building all the trapping components on a microfabricated structure. We propose instead a design (trap A) based on two chips facing each other [see subfigure (b)]. Each (...)
Simulations des trajectoires
The evolution of the atom in the time-varying electric field being adiabatic, we can simply write ![\mathcal{E}(t)=\mathcal{E}[E(t)]](local/cache-TeX/ed96afca102579018f1048c3660826ad.png "\mathcal{E}(t)=\mathcal{E}[E(t)]"){kind=small}
. From 
, it is easy to derive a formula for the electric field modulus 
, and therefore for the potential energy of a trapped atom.
Performances attendues
We have studied the trapping characteristics for a wide range of
parameters, especially the voltage 
which controls the mean
electric field experienced by the atoms, the voltage 
and
the frequency 
of the a.c. field, the last two together
controlling the confinement.
