Quantum information processing with semiconductor macroatoms

An all optical implementation of quantum information processing with semico nductor macroatoms is proposed. Our quantum hardware consists of an array o f quantum dots and the computational degrees of freedom are energy-selected interband optical transitions. The quantum-computing strategy exploits exc iton-exciton interactions driven by ultrafast multicolor laser pulses. Cont rary to existing proposals based on charge excitations, our approach does n ot require time-dependent electric fields, thus allowing for a subpicosecon d, decoherence-free, operation time scale in realistic semiconductor nanost ructures.