title: Controllable anisotropic exchange coupling between spin qubits in quantum dots.
abstract: The exchange coupling between quantum dot spin qubits is isotropic, which restricts the types of quantum gates that can be formed. Here, we propose a method for controlling anisotropic interactions between spins arranged in a bus geometry. The symmetry is broken by an external magnetic field, resulting in XXZ-type interactions that can efficiently generate maximally entangled Greenberger-Horne-Zeilinger states or universal gate sets for exchange-only quantum computing. We exploit the XXZ couplings to propose a qubit scheme, based on double dots.
authors.affiliation: Department of Physics, University of Wisconsin–Madison, 53706, USA.
authors.forename: Yun-Pil
authors.initials: YP
authors.lastname: Shim
authors.forename: Sangchul
authors.initials: S
authors.lastname: Oh
authors.forename: Xuedong
authors.initials: X
authors.lastname: Hu
authors.forename: Mark
authors.initials: M
authors.lastname: Friesen