Coherent charge qubits based on GaAs quantum dots with a built-in barrier

摘要

We investigated the use of quantum bits (qubits)-semiconductor quantum dots containing one electron and each consisting of two-tunnel-connected parts-as basic elements of the quantum computer. The numerical solution of a Schiodinger equation taking account of the Coulomb field of adjacent electrons shows that in such structures the realization of a full set of basic logic operations, which are necessary for fulfillment of quantum computations is possible. Durations of one-and two-qubit operations versus qubit geometry are obtained. Decoherence rates due to spontaneous emission of phonons and acoustic phonons (both piezoelectric and deformation) are evaluated. Analysis of these rates shows the proposed qubit to be coherent enough to work for an unlimited time.