X. Luo

Quasispin model for macroscopic quantum tunneling between two coupled Bose-Einstein condensates

The system of two coupled Bose-Einstein condensates is mapped onto a uniaxial spin with an applied magnetic field. The mean-field interaction, the coupling, and the asymmetry or the detuning correspond to the anisotropy, the transverse field, and the longitudinal field, respectively. A generalized Bloch equation is derived. In the low barrier limit for the quasispin model, the tunneling rate is analyzed with an imaginary-time path-integral method. The dependence of the tunneling rate on the system parameters is obtained. The crossover temperature T-c from the thermal regime to the quantum regime is estimated. Below T-c quantum tunneling prevails, otherwise thermal activation dominates.

Stable orbits embedded in a chaotic attractor for a trapped ion interacting with a laser field

The interaction between a trapped ion and a resonant laser standing wave is studied under the analytical approximation. Periodic orbits next to the heteroclinic one and their stability conditions are derived from the Rayleigh perturbation method. Theoretical analysis reveals the stable periodic orbits to be embedded in the Melnikov chaotic attractor. The corresponding numerical results show that fitting control parameters into the stability conditions can control chaos in the system.

ORIGIN AND MANIFESTATION OF THE ANHARMONIC POTENTIAL FELT BY AN ION-CLOUD IN AN ACTUAL PAUL TRAP

The anharmonic potential felt by a single-species ions confined in a rf quadrupole trap which results from a non-ideal trap configuration and the charge distribution of the ion cloud is studied. The rf resonance-absorption spectra are explained by a Duffing oscillator and a representation of the line-shape parameter η is derived. Forη > 0.77, the electric signals will exhibit hysteresis. The relation with the anharmonic potential is discussed.

All-quantized Jaynes-Cummings interaction for a trapped ultracold ion *

We propose an all-quantized Jaynes-Cummings (JC) interaction between a trapped ultracold ion with a quantized radiation held. The carrier excitation gives the usual JC model in cavity QED, but the red and blue excitations will result in three-body interactions analogous to a two-mode problem in quantum optics

Nonlinear Jaynes-Cummings Dynamics of a Trapped Ion Under a Dressed-State Description

Introducing a dressed-state description, we show that a trapped ion in a standing wave field can be described by a nonlinear Jaynes-Cummings model different from the counterpart of Vogel and Matos Filho [Phys. Rev. A 52 (1995) 4214] in several aspects, which may carry important implications for the preparation and reconstruction of the nonclassical states of a trapped ion.