Mechanically probing coherent tunneling in a double quantum dot

We study theoretically the interaction between the charge dynamics of a few-electron double quantum dot and a capacitively coupled atomic force microscopy cantilever, a setup realized in several recent experiments. We demonstrate that the dot-induced frequency shift and damping of the cantilever can be used as a sensitive probe of coherent interdot tunneling, and that these effects can be used to quantitatively extract both the magnitude of the coherent interdot tunneling and (in some cases) the value of the double-dot T-1 time. We also show how the adiabatic modulation of the dot eigenstates by the cantilever motion leads to substantial effects which are completely absent in the more studied single-dot case.