A theoretical investigation into the microwave spectroscopy of a   phosphorus-donor charge-qubit in silicon: Coherent control in the Si:P   quantum computer architecture
  We present a theoretical analysis of a microwave spectroscopy experiment on a charge qubit defined by a P$_2^+$ donor pair in silicon, for which we calculate Hamiltonian parameters using the effective-mass theory of shallow donors. We solve the master equation of the driven system in a dissipative environment to predict experimental outcomes. We describe how to calculate physical parameters of the system from such experimental results, including the dephasing time, $T_2$, and the ratio of the resonant Rabi frequency to the relaxation rate. Finally we calculate probability distributions for experimentally relevant system parameters for a particular fabrication regime. 
C.J. Wellard, L.C.L. Hollenberg, S. Das Sarma