  This work presents a step furthering a new perspective of proactive control
of the spin-exciton dynamics in the quantum limit. Laser manipulation of
spin-polarized optical excitations in a semiconductor nanodot is used to
control the spin dynamics of two interacting excitons. Shaping of femtosecond
laser pulses keeps the quantum operation within the decoherence time.
Computation of the fidelity of the operations and application to the complete
solution of a basic quantum computing algorithm demonstrate in theory the
feasibility of quantum control.
