Fast and noise-resistant ion-trap quantum computation with inherent dynamical decoupling

We propose a scheme for realizing quantum logic gates between any pair of ions confined in a linear trap with a pair of laser beams tuned to the carrier. The striking feature of the scheme is that the carrier excitation accompanying the spin-motion coupling does not affect the gate dynamics. As a consequence, the gate not only is much more insensitive to motional heating but also can operate at a higher speed compared to the previous schemes. The other important advantages are that the gate speed does not need to be inversely proportional to the number of ions in the chain, and the accompanying carrier drive results in dynamical decoupling, making the gate performance robust against dephasing noises. We show that for the same error sources the gate infidelity can be decreased by about ten times compared with previous schemes.