  We investigate an optically driven quantum computer based on electric dipole
transitions within coupled single-electron quantum dots. Our quantum register
consists of a freestanding n-type pillar containing a series of pair wise
coupled asymmetric quantum dots, each with a slightly different energy
structure, and with grounding leads at the top and bottom of the pillar.
Asymmetric quantum wells confine electrons along the pillar axis and a
negatively biased gate wrapped around the center of the pillar allows for
electrostatic confinement in the radial direction. We self-consistently solve
coupled Schrodinger and Poisson equations and develop a design for a
three-qubit quantum register. Our results indicate that a single gate electrode
can be used to localize a single electron in each of the quantum dots. Adjacent
dots are strongly coupled by electric dipole-dipole interactions arising from
the dot asymmetry, thus enabling rapid computation rates. The dots are tailored
to minimize dephasing due to spontaneous emission and phonon scattering and to
maximize the number of computation cycles. The design is scalable to a large
number of qubits.
