Physics & Astronomy Undergraduate Honours Theseshttp://hdl.handle.net/2429/5472014-04-24T11:31:54Z2014-04-24T11:31:54ZSearching for solitons in the magnetosphere of a magnetarWong, Melody Candacehttp://hdl.handle.net/2429/463542014-04-11T09:27:20Z2013-04-01T00:00:00ZWe describe a non-pertrubative method of searching for solitary waves travelling through the
magnetosphere of a magnetar. The wave will be supported by the combined e ects of nonlinearity
and dispersion caused by the presence of a quantum electrodynamic (QED) vacuum in a strongly
magnetized eld and by a strongly magnetized plasma of the magnetosphere. Using this method,
we have found a soliton in the form of an in nite current sheet. The method and the results of
this paper could be conducive to research studying the emission of strongly magnetized stars.
2013-04-01T00:00:00ZSingle color photoassociation spectroscopy of ⁶Li₂ and ⁸⁵Rb₂Haw, Magnushttp://hdl.handle.net/2429/433532014-04-07T18:09:56Z2012-09-01T00:00:00ZSingle color photoassociation (PA) of ⁸⁵Rb₂ and ⁶Li₂ was achieved in an optical dipole trap with the goal of measuring new vibrational levels of the 1³∑g state of ⁶Li₂. Initial benchmark tests using Rb were performed to determine the optimum conditions for observing photoassociation on the apparatus: >.5 kW/cm² PA laser intensity, high density, low temperature (∼ 10ɲK), and long hold times (>1s). These tests with Rb also revealed discrepancies between dipole trap PA data and spectra taken in a magneto-optic trap on another experiment (MAT).
Initial calculations for the locations of the ⁶Li₂ lines were carried out using fitted
potentials provided to us by Nikesh Dattani [5]. We observed seven ⁶Li₂ PA lines that were within 1 cm⁻¹ of the predicted values. Because of this good agreement between theory and measurement for all seven lines, we are confident that these lines are indeed vibrational levels of the 1³∑g state of Li₂. Additional studies of two of these peaks revealed five or six-fold splitting due to the magnetic field.
2012-09-01T00:00:00ZPhotonuclear Sum Rules for 6He.Goerke, Raymondhttp://hdl.handle.net/2429/373112011-09-15T09:07:24Z2011-01-01T00:00:00ZWe perform the ab-initio calculation of photonuclear sum rules for 4He and 6He
using semi-realistic potentials. Our results include the first ab-initio calculation
of the electric polarizabililty of 6He. We perform the calculation by expanding the
the wavefunctions in a Hyperspherical Harmonic basis and solving the Schr¨odinger
equation exactly. Model space trunction effects are estimated by incrementing the
size of the Hilbert space, and evaluating the convergence pattern. We also compute
sum rules by integrating the theoretically computed cross section available from the
literature. Full convergence is not yet achieved. A discussion of the preliminary
results is presented. Future work, taking advantage of negligible symmetries in the
hyperspherical harmonic basis, should be able to achieve full convergence.
2011-01-01T00:00:00ZA Study of Excited State Atoms in Cold Atom Traps and a test of the Reif Model to Determine Trap Depth.Evetts, Nathanhttp://hdl.handle.net/2429/368582011-08-24T09:18:13Z2011-01-01T00:00:00ZThe motivation, theory and applications of atomic traps are briefly reviewed
before delving into the primary motivation for the research: the disagreement
between theory and experiment for the calculation of trap loss rate
constants (< σv >) for Rubidium Magneto-Optical Traps. We use a pure
magnetic trap to calibrate for the density of background Rubidium in our
system while varying this density and measuring the loss and loading rates
for multiple magnetic traps for which the trap depth has been measured
previously. This variation of density allows us to infer < σv >, a quantity
whose behaviour we attempt to explain in relation to the the excited state
fraction of the trapped atoms. We find a strong correlation between the excited
state fraction and the loss rate constant which we are, unfortunately,
unable to quantify due to data quality issues. In addition to this study,
experimental evidence for the confirmation of the Reif Model is provided as
well as a new method (based on this model) for measuring the depth of a
magneto-optical trap.
2011-01-01T00:00:00Z