Auxiliary-level-assisted operations with charge qubits in semiconductors

Abstract

We present a new scheme for rotations of a charge qubit associated with a singly ionized pair of donor atoms in a semiconductor host. The logical states of such a qubit proposed recently by Hollenberg et al. are defined by the lowest two energy states of the remaining valence electron localized around one or another donor. We show that an electron located initially at one donor site can be transferred to another donor site via an auxiliary molecular level formed upon the hybridization of the excited states of two donors. The electron transfer is driven by a single resonant microwave pulse in the case that the energies of the lowest donor states coincide or two resonant pulses in the case that they differ from each other. Depending on the pulse parameters, various one-qubit operations, including the phase gate, the NOT gate, and the Hadamard gate, can be realized in short times. Decoherence of an electron due to the interaction with acoustic phonons is analyzed and shown to be weak enough for coherent qubit manipulation being possible, at least in the proof-of-principle experiments on one-qubit devices.

Extended version of cond-mat/0411605 with detailed discussion of phonon-induced decoherence including dephasing and relaxation; to be published in JETP

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Cited by in corpus (5)

• Rabi oscillations in the four-level double-dot structure under the influence of the resonant pulse
• Single-qubit operations in the double-donor structure driven by optical and voltage pulses
• Single-qubit operations in the double-donor structure driven by strongly detuned optical pulses
• Phonon-induced decoherence of the two-level quantum subsystem due to relaxation and dephasing processes
• Laser-induced operations with charge qubits in a double-well nanostructure