A scheme for ground-state cooling of a mechanical resonator by single- and two-phonon processes is analyzed. The mechanical resonator is coupled to two coupled quantum dots forming an effective Λ-type three-level structure and connected with two normal metal leads. The quantum dots are driven by two light fields; by choosing appropriate parameters, the electron can be trapped in the dark state of the system, a superposition of the two ground states. When the single-phonon absorption and emission processes are dominant, under the weak (strong) ...
