24 research outputs found
High-precision calculations of dispersion coefficients, static dipole polarizabilities, and atom-wall interaction constants for alkali-metal atoms
The van der Waals coefficients for the alkali-metal atoms from Na to Fr
interacting in their ground states, are calculated using relativistic ab initio
methods. The accuracy of the calculations is estimated by also evaluating
atomic static electric dipole polarizabilities and coefficients for the
interaction of the atoms with a perfectly conducting wall. The results are in
excellent agreement with the latest data from ultra-cold collisions and from
studies of magnetic field induced Feshbach resonances in Na and Rb. For Cs we
provide critically needed data for ultra-cold collision studies
Optimizing the fast Rydberg quantum gate
The fast phase gate scheme, in which the qubits are atoms confined in sites
of an optical lattice, and gate operations are mediated by excitation of
Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000).
A potential source of decoherence in this system derives from motional heating,
which occurs if the ground and Rydberg states of the atom move in different
optical lattice potentials. We propose to minimize this effect by choosing the
lattice photon frequency \omega so that the ground and Rydberg states have the
same frequency-dependent polarizability \alpha(omega). The results are
presented for the case of Rb.Comment: 5 pages, submitted to PR
Slowing and cooling molecules and neutral atoms by time-varying electric field gradients
A method of slowing, accelerating, cooling, and bunching molecules and
neutral atoms using time-varying electric field gradients is demonstrated with
cesium atoms in a fountain. The effects are measured and found to be in
agreement with calculation. Time-varying electric field gradient slowing and
cooling is applicable to atoms that have large dipole polarizabilities,
including atoms that are not amenable to laser slowing and cooling, to Rydberg
atoms, and to molecules, especially polar molecules with large electric dipole
moments. The possible applications of this method include slowing and cooling
thermal beams of atoms and molecules, launching cold atoms from a trap into a
fountain, and measuring atomic dipole polarizabilities.Comment: 13 pages, 10 figures. Scheduled for publication in Nov. 1 Phys. Rev.
Unified Treatment of Asymptotic van der Waals Forces
In a framework for long-range density-functional theory we present a unified
full-field treatment of the asymptotic van der Waals interaction for atoms,
molecules, surfaces, and other objects. The only input needed consists of the
electron densities of the interacting fragments and the static polarizability
or the static image plane, which can be easily evaluated in a ground-state
density-functional calculation for each fragment. Results for separated atoms,
molecules, and for atoms/molecules outside surfaces are in agreement with those
of other, more elaborate, calculations.Comment: 6 pages, 5 figure
Measurement of the scalar polarizability of very highly excited states of caesium
van Raan AFJ, Baum G, Raith W. Measurement of the scalar polarizability of very highly excited states of caesium. J.Phys. B. 1976;9(12):L349-L352.First results on the scalar polarizability alpha 0 of a number of very highly excited p states of Cs (40 109 Å3 were measured; the dependence of the polarizability as a function of the principal quantum number n was found to be in agreement with the expected n7 behaviour