School of Physics - Research Publications
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ItemImaging the Sunyaev Zel'dovich Effect using ACBAR on Viper(Cambridge University Press, 2004)During 2001 and 2002, observations of several X-ray bright clusters of galaxies were conducted using the ACBAR Bolometer Array on the South Pole Viper telescope. A multi-frequency analysis of these clusters is currently underway. This multi-frequency analysis includes 150, 220 and 275 GHz data from ACBAR, X-ray imaging and spectroscopy from Chandra and XMM-Newton, and weak lensing data from the CTIO 4m Blanco telescope. We describe here how ACBAR can be used to create fully sampled cluster images and present such images for four of the clusters in our sample; Abell 3266, Abell 3827, Abell S1063 and 1E0657-56. In these images, the Sunyaev-Zel'dovich Effect is clearly detected.
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ItemTransport and disruption of Bose-Einstein condensates in optical lattices(AMER PHYSICAL SOC, 2004-03)
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ItemEffect of soliton and vortex geometry on the transport of Bose-Einstein condensates in optical lattices(AMER PHYSICAL SOC, 2004-06)
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ItemCoherence properties of light propagated through a scattering medium( 2004)Partially-coherent, quasi-monochromatic optical fields are fully described by their Mutual Optical Intensity (MOI) or the phase-space equivalent, the Generalised Radiance (GR). This paper reports on the application of a propagation-based phase-space tomographic technique for determining both the MOI and the GR of wavefields. This method is applied to the reconstruction of the MOI and the GR of an optical wavefield propagated through a suspension of ~10 μm diameter polystyrene spheres.
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ItemX-ray phase imaging: Demonstration of extended conditions with homogeneous objects(OPTICAL SOC AMER, 2004-06-28)We discuss contrast formation in a propagating x-ray beam. We consider the validity conditions for linear relations based on the transport-of-intensity equation (TIE) and on contrast transfer functions (CTFs). From a single diffracted image, we recover the thickness of a homogeneous object which has substantial absorption and a phase-shift of --0.37 radian.
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ItemOff-resonant defocus-contrast imaging of cold atoms(OPTICAL SOC AMER, 2004-02-01)We demonstrate the retrieval of column-density images of cold atoms, using a noninterferometric phase-recovery technique based on a single off-resonant and defocused intensity image. The quantitative column density is retrieved via Fourier inversion and remains robust with respect to detuning and defocus. The technique offers excellent prospects for simple, nondestructive imaging of atoms in magnetic and optical traps and condensates.
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ItemDecoherence, the measurement problem, and interpretations of quantum mechanics(AMER PHYSICAL SOC, 2004-10)
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ItemAUTC Physics Project: Learning outcomes and curriculum development(Uniserve Science, 2004)
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ItemControlled vortex-sound interactions in atomic Bose-Einstein condensates.(American Physical Society (APS), 2004-04-23)The low temperature dynamics of a vortex in a trapped quasi-two-dimensional Bose-Einstein condensate are studied quantitatively. Precession of an off-centered vortex in a dimple trap, embedded in a weaker harmonic trap, leads to the emission of sound in a dipolar radiation pattern. Sound emission and reabsorption can be controlled by varying the depth of the dimple. In a shallow dimple, the power emitted is proportional to the vortex acceleration-squared over the precession frequency, whereas for a deep dimple, periodic sound reabsorption stabilizes the vortex against radiation-induced decay.