Heating of trapped atoms near thermal surfaces

Institut für Physik, Universität Potsdam Am Neuen Palais 10, 14469 Potsdam, Germany

Received: 8 February 1999
Accepted: 24 June 1999

Abstract

We study the electromagnetic coupling and concomitant heating of a particle in a miniaturized trap close to a solid surface. Two dominant heating mechanisms are identified: proximity fields generated by thermally excited currents in the absorbing solid and time-dependent image potentials due to elastic surface distortions (Rayleigh phonons). Estimates for the lifetime of the trap ground state are given. Ions are particularly sensitive to electric proximity fields: for a silver substrate, we find a lifetime below one second at distances closer than some ten to the surface. Neutral atoms may approach the surface more closely: if they have a magnetic moment, a minimum distance of one μm is estimated in tight traps, the heat being transferred via magnetic proximity fields. For spinless atoms, heat is transferred by inelastic scattering of virtual photons off surface phonons. The corresponding lifetime, however, is estimated to be extremely long compared to the timescale of typical experiments.