Singlet-triplet relaxation in two-electron silicon quantum dots

The experimental group at Wisconsin recently showed that there are long-lived triplet states in two-electron silicon quantum dots. Marta Prada, Robert Blick and I have shown that the relaxation of states of this kind arises from a mixture of coupling to the nuclei and coupling to phonons. The proportions in this mix depend strongly on the applied field. The relaxation times can be quite long, of the order of seconds, in the appropriate conditions.