Quantum computing with magnetic atoms in optical lattices of reduced periodicity

We investigate the feasibility of combining Raman optical lattices with a quantum computing architecture based on lattice-confined magnetically interacting neutral atoms. A particular advantage of the standing Raman field lattices comes from reduced interatomic separations leading to increased interatomic interactions and improved multiqubit gate performance. Specifically, we analyze a $J=3∕2$ Zeeman system placed in ${\sigma }_{+}\text{−}{\sigma }_{-}$ Raman fields which exhibit $\lambda ∕4$ periodicity. We find that the resulting controlled-NOT (CNOT) gate operations times are in the order of millisecond. We also investigate motional and magnetic-field induced decoherences specific to the proposed architecture.

Figure 1

(Color online) The standing wave Raman atom-field configuration is composed of four laser fields. For $J_g=3∕2$ the optically coupled states are either $M=-3∕2,1∕2$ or $M=-1∕2,3∕2$ and the lower-manifold splitting is due to the Zeeman interaction.

Figure 2

(Color online) Optical potentials, Eq. (4), for the optimal choice of Raman detuning $\delta$. While each individual potential $U_{+}\left(z\right)$ and $U_{-}\left(z\right)$ has a $\lambda ∕2$ periodicity, the minima of the potentials interweave, with the resulting distance between trapped atoms being $\lambda ∕4$.