Heating of trapped atoms near thermal surfaces

We study the electromagnetic coupling and concomitant heating of a particle in a miniaturized trap close to a solid surface. Two dominant heating mech anisms are identified: proximity fields generated by thermally excited curr ents in the absorbing solid and time-dependent image potentials due to elas tic surface distortions (Rayleigh phonons). Estimates for the lifetime of t he trap ground state are given. Ions are particularly sensitive to electric proximity fields: for a silver substrate, we find a lifetime below one sec ond at distances closer than some ten mu m to the surface. Neutral sterns m ay approach the surface more closely: if they have a magnetic moment, a min imum distance of one mu m is estimated in tight traps, the heat being trans ferred via magnetic proximity fields. For spinless atoms, heat is transferr ed by inelastic scattering of virtual photons off surface phonons. The corr esponding lifetime, however, is estimated to be extremely long compared to the timescale of typical experiments.