The practical construction of scalable quantum-computer hardware capable of executing nontrivial quantum algorithms will require the juxtaposition of different types of quantum systems. We analyze a modular ion trap quantum-computer architecture with a hierarchy of interactions that can scale to very large numbers of qubits. Local entangling quantum gates… (More)
We review recent theoretical proposals for implementation of quantum computing and quantum communication with atoms. The first example deals with the realization of a universal quantum simulator with atoms and ions. The second example outlines the implementation of a quantum repeater with atomic ensembles.
We perform a quantum simulation of the Ising model with a transverse field using a collection of three trapped atomic ion spins. By adiabatically manipulating the Hamiltonian, we directly probe the ground state for a wide range of fields and form of the Ising couplings, leading to a phase diagram of magnetic order in this microscopic system. The technique… (More)
We propose a method to implement cavity QED and quantum-information processing in high-Q cavities with a single trapped but nonlocalized atom. The system is beyond the Lamb-Dicke limit due to the atomic thermal motion. Our method is based on adiabatic passages, which make the relevant dynamics insensitive to the randomness of the atom position with an… (More)
PACS 03.67.Lx – Quantum computation architectures and implementations PACS 32.80.Qk – Coherent control of atomic interactions with photons PACS 03.67.Pp – Quantum error correction and other methods for protection against decoherence Abstract – We propose a large-scale quantum computer architecture by more easily stabilizing a single large linear ion chain… (More)
We consider two approaches to dark-spin-mediated quantum computing in hybrid solid-state spin architectures. First, we review the notion of eigenmode-mediated unpolarized spin-chain state transfer and extend the analysis to various experimentally relevant imperfections: quenched disorder, dynamical decoherence, and uncompensated long-range coupling. In… (More)
The router is a key element for a network. We describe a scheme to realize genuine quantum routing of single-photon pulses based on cascading of conditional quantum gates in a Mach-Zehnder interferometer and report a proof-of-principle experiment for its demonstration using linear optics quantum gates. The polarization of the control photon routes in a… (More)
We propose a scheme to realize scalable quantum computation in a planar ion crystal confined by a Paul trap. We show that the inevitable in-plane micromotion affects the gate design via three separate effects: renormalization of the equilibrium positions, coupling to the transverse motional modes, and amplitude modulation in the addressing beam. We… (More)