  A vital requirement for a quantum computer is the ability to locally address,
with high fidelity, any of its qubits without affecting their neighbors. We
propose an addressing method using composite sequences of laser pulses, which
reduces dramatically the addressing error in a lattice of closely spaced atoms
or ions, and at the same time significantly enhances the robustness of qubit
manipulations. To this end, we design novel high-fidelity composite pulses for
the most important single-qubit operations. In principle, this method allows
one to beat the diffraction limit, for only atoms situated in a small spatial
region around the center of the laser beam are excited, well within the laser
beam waist.
