Magnet designs for a crystal-lattice quantum computer

A quantum computer using nuclear spins in a crystal lattice requires a meth od for addressing individual quantum bits. This identification can be achie ved with a spatially varying magnetic field. Spins at different lattice sit es can have distinguishable Zeeman frequencies allowing initialization, log ic operations, and measurements to be performed through radio frequency (rf ) pulse techniques. Here, we present magnet designs that have gradients bet ween 1 and 20 T/mu m, which are necessary to realize quantum computation wi th particular crystals. PACS: 03.67.Lx; 76.60.Pc; 85.70.w.