The interference pattern of the resonance fluorescence from a J51/2 to J51/2 transition of two identical
atoms confined in a three-dimensional harmonic potential is calculated. The thermal motion of the atoms is
included. Agreement is obtained with experiments @U. Eichmann et al., Phys. Rev. Lett. 70, 2359 ~1993!#.
Contrary to some theoretical predictions, but in agreement with the present calculations, a fringe visibility
greater than 50% can be observed with polarization-selective detection. The dependence of the fringe visibility
on polarization has a simple interpretation, based on whether or not it is possible in principle to determine
which atom emitted the photon.