Ion Chains in Optical Lattices as Simple Quantum Glasses

Tommaso Roscilde

Aditi Sen De, Ujjwal Sen, Maciej Lewenstein +3 more

We report our research on disordered complex systems using cold gases and trapped ions, and address the possibility of using complex systems for quantum information processing. Two simple paradigmatic models of disordered complex systems are revisited here. The first one corresponds to a short range disordered Ising Hamiltonian (spin glasses), which can be implemented with a Bose-Fermi (Bose-Bose) mixture in a disordered optical lattice. The second model we address here is a long range disordered Hamiltonian, characteristic of neural networks (Hopfield model), which can be implemented in a chain of trapped ions with appropriately designed interactions.

Ivan Deutsch, Poul Jessen

Jessen

Thaned Pruttivarasin, Michael T. Ramm, Ishan Talukdar +2 more

We show that a chain of trapped ions embedded in microtraps generated by an optical lattice can be used to study oscillator models related to dry friction and energy transport. Numerical calculations with realistic experimental parameters demonstrate that both static and dynamic properties of the ion chain change significantly as the optical lattice power is varied. Finally, we lay out an experimental scheme to use the spin degree of freedom to probe the phase space structure and quantum critical behavior of the ion chain.

L. Pierre de Rochemont

Stimulated photon echoes from optically active ions in glasses have long been used to study effects related to the molecular dynamics of the host medium in the immediate vicinity of the active site. Recently, photon echoes have been suggested for use in high speed optical circuitry and in optical memory storage. This technology offers unique systems potential because it permits analog spatial information to be processed at digital-gate intervals. Because active ions can be incorporated into the matrix of a glass in higher concentrations than they can be doped into the lattice of a crystal, amorphous solids are potentially more suitable host materials for these applications than are crystals. In this paper the Judd-Ofelt parameters and the Einstein coefficients are used to calculate the time evolution of population gratings and stimulated echo intensities at 0.8 and 1.22μm from an inverted ensemble of erbium ions in doped (2 mol. %) heavy-metal fluorozirconate glass. A simple mathematical model composed of constant-condition interaction and relaxation sequences is invoked.