We describe a fast quantum computer based on optically controlled electron
spins in charged quantum dots that are coupled to microcavities. This scheme
uses broad-band optical pulses to rotate electron spins and provide the clock
signal to the system. Non-local two-qubit gates are performed by phase shifts
induced by electron spins on laser pulses propagating along a shared waveguide.
Numerical simulations of this scheme demonstrate high-fidelity single-qubit and
two-qubit gates with operation times comparable to the inverse Zeeman
frequency.Comment: 4 pages, 4 figures, introduction is clarified, the section on
two-qubit gates was expanded and much more detail about gate fidelities is
given, figures were modified, one figure replaced with a figure showing gate
fidelities for relevant parameter