  We propose a quantum computer architecture involving substitutional donors in
photonic-crystal silicon cavities and the optical initialization, manipulation,
and detection processes already demonstrated in ion traps and other atomic
systems. Our scheme considerably simplifies the implementation of the building
blocks for the successful operation of silicon-based solid-state quantum
computers, including positioning of the donors, realization of one- and
two-qubit gates, initialization and readout of the qubits. Detailed
consideration of the processes involved, using state-of-the-art values for the
relevant parameters, indicates that this architecture might lead to errors per
gate compatible with scalable quantum computation.
