Bright solitary waves and non-equilibrium dynamics in atomic Bose-Einstein condensates

In this thesis we investigate the static properties and non-equilibrium dynamics of bright solitary waves in atomic Bose-Einstein condensates in the zero-temperature limit, and we investigate the non-equilibrium dynamics of a driven atomic Bose-Einstein condensate at finite temperature. Bright solitary waves in atomic Bose-Einstein condensates are non-dispersive and soliton-like matter-waves which could be used in future atom-interferometry experiments. Using the mean-field, Gross-Pitaevskii description, we propose an experimental scheme to generate pairs of bright solitary waves with controlled velocity and relative phase; this scheme could form an important part of a future atom interferometer, and we demonstrate that it can also be used to test the validity of the mean-field model of bright solitary waves. We also develop a method to quantitatively assess how soliton-like static, three-dimensional bright solitary waves are; this assessment is particularly relevant for the design of future experiments. In reality, the non-zero temperatures and highly non-equilibrium dynamics occurring in a bright solitary wave interferometer are likely to necessitate a theoretical description which explicitly accounts for the non-condensate fraction. We show that a second-order, number-conserving description offers a minimal self-consistent treatment of the relevant condensate -- non-condensate interactions at low temperatures and for moderate non-condensate fractions. We develop a method to obtain a fully-dynamical numerical solution to the integro-differential equations of motion of this description, and solve these equations for a driven, quasi-one-dimensional test system. We show that rapid non-condensate growth predicted by lower-order descriptions, and associated with linear dynamical instabilities, can be damped by the self-consistent treatment of interactions included in the second-order description

Occupational and life stress in nursing: Is there a relationship?

A population of two hundred and twenty nurses involved in direct patient care in a regional hospital were surveyed to assess if a relationship exists between occupational and life stress. A cross sectional survey design was used. The questionnaire contained four distinct categories: demographic information, Nurses\u27 Stress Scale, a Life Events Inventory and a social support scale. A return rate of 49.5% was obtained, and several completed questionnaires were rejected, leaving the data from 1.04 questionnaires to be analysed. The nurses in this population reported low scores tor both occupational and life stress. However, the instrument used to calculate the occupational stress levels did not prove to be reliable for this population, as indicated by a low Cronbach\u27s alpha score. A Pearson\u27s correlation analysis was computed for all of the variables studied. The only significant correlation found was life stress with occupational stress (r = .23 with p = .01~. Multiple regression using the maximum R2 method revealed that a combination of three variables; life stress, working· status and social support accounted for 7.6% of the variance tor the dependent variable occupational stress (p=.05)

Realizing bright-matter-wave-soliton collisions with controlled relative phase

We propose a method to split the ground state of an attractively interacting atomic Bose-Einstein condensate into two bright solitary waves with controlled relative phase and velocity. We analyze the stability of these waves against their subsequent recollisions at the center of a cylindrically symmetric, prolate harmonic trap as a function of relative phase, velocity, and trap anisotropy. We show that the collisional stability is strongly dependent on relative phase at low velocity, and we identify previously unobserved oscillations in the collisional stability as a function of the trap anisotropy. An experimental implementation of our method would determine the validity of the mean-field description of bright solitary waves and could prove to be an important step toward atom interferometry experiments involving bright solitary waves