



01407nas a2200157   4500008004100000245006700041210006700108260001400175490000700189520094200196100002201138700001701160700001901177700001601196856003701212       2011                        eng d00aFast and robust quantum computation with ionic Wigner crystals0 aFast and robust quantum computation with ionic Wigner crystals  c2011/4/150 v833 aWe present a detailed analysis of the modulated-carrier quantum phase gate implemented with Wigner crystals of ions confined in Penning traps. We elaborate on a recent scheme, proposed by two of the authors, to engineer two-body interactions between ions in such crystals. We analyze for the first time the situation in which the cyclotron (w_c) and the crystal rotation (w_r) frequencies do not fulfill the condition w_c=2w_r. It is shown that even in the presence of the magnetic field in the rotating frame the many-body (classical) Hamiltonian describing small oscillations from the ion equilibrium positions can be recast in canonical form. As a consequence, we are able to demonstrate that fast and robust two-qubit gates are achievable within the current experimental limitations. Moreover, we describe a realization of the state-dependent sign-changing dipole forces needed to realize the investigated quantum computing scheme.
1 aBaltrusch, J., D.1 aNegretti, A.1 aTaylor, J., M.1 aCalarco, T.  uhttp://arxiv.org/abs/1011.5616v2