Rabi oscillations, coherent properties and model qubits in two-level donor systems under terahertz radiation

Quantum confinement, magnetic-field effects, and laser coupling with the two low-lying states of electrons bound to donor impurities in semiconductors may be used to coherently manipulate the two-level donor system in order to establish the appropriate operational conditions of basic quantum bits (qubits) for solid-state based quantum computers. Here we present a detailed theoretical calculation of the damped Rabi oscillations and time evolution of the 1s and 2p+ donor states in bulk GaAs under an external magnetic field and in the presence of terahertz laser radiation, and their influence on the measured photocurrent. We also detail the possible experimental conditions under which decoherence is weak and qubit operations are efficiently controlled.