Predicted ultrafast single-qubit operations in semiconductor quantum dots

Several proposals for scalable quantum computation rely on the manipulation of the spin of individual electrons in semiconductors. We show that a spin-sensitive optical Stark effect will produce a coherent rotation of spin in quantum dots containing a single electron. The calculated magnitude of the effective magnetic field depends on the dot band gap and the strain. We predict that in InAs∕InP dots, for reasonable experimental parameters, the magnitude of the rotation is sufficient and the intrinsic error is low enough for them to serve as elements of a quantum-dot-based quantum computer.