- School of Physics - Research Publications
School of Physics - Research Publications
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ItemAnomalous quantum reflection of Bose-Einstein condensates from a silicon surface: The role of dynamical excitationsScott, RG ; Martin, AM ; Fromhold, TM ; Sheard, FW (AMERICAN PHYSICAL SOC, 2005-08-12)We investigate the effect of interatomic interactions on the quantum-mechanical reflection of Bose-Einstein condensates from regions of rapid potential variation. The reflection process depends critically on the density and incident velocity of the condensate. For low densities and high velocities, the atom cloud has almost the same form before and after reflection. Conversely, at high densities and low velocities, the reflection process generates solitons and vortex rings that fragment the condensate. We show that this fragmentation can explain the anomalously low reflection probabilities recently measured for low-velocity condensates incident on a silicon surface.
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ItemDiffraction-contrast imaging of cold atomsTurner, Lincoln D. ; Domen, Kenian E. F. M. ; Scholten, Robert E. ( 2005-01)We consider the inverse problem of in-line holography, applied to minimally-destructive imagingof cold atom clouds. Absorption imaging near resonance provides a simple, but destructive measurementof atom column density. Imaging off resonance greatly reduces heating, and sequential imagesmay be taken. Under the conditions required for off-resonant imaging, the generally-intractable inverseproblem may be linearized. A minimally-destructive, quantitative and high-resolution imageof the atom cloud column density is then retrieved from a single diffraction pattern.
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ItemA numerical optimal control approach to the design of an optical fibre-based evanescent field sensorDower, PM ; Farrell, PM ; Gibson, BC (Elsevier BV, 2005-01-01)
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ItemIon beam induced charge and numerical modeling study of novel detector devices for single ion implantationHopf, T ; Jamieson, DN ; Hearne, SM ; Yang, C ; Pakes, CI ; Dzurak, AS ; Gauja, E ; Clark, RG (ELSEVIER, 2005-04)
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ItemNear-infrared chemiluminescence from the oxidation of ammonia in aqueous alkaline solutionFrancis, PS ; Barnett, NW ; Smith, TA ; Spizzirri, PG ; Wang, XQ ; Krausz, E (WILEY, 2005)The chemiluminescent oxidation of ammonia with hypobromite in aqueous alkaline solution evokes a broadly distributed emission in the near-infrared region, with intensity maxima at 1055 nm and 1270 nm.
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ItemSelf-induced decoherence approach: Strong limitations on its validity in a simple spin bath model and on its general physical relevanceSchlosshauer, M (AMER PHYSICAL SOC, 2005-07)
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ItemEmergence and decay of turbulence in stirred atomic Bose-Einstein condensates.Parker, NG ; Adams, CS (American Physical Society (APS), 2005-09-30)We show that "weak" elliptical deformation of an atomic Bose-Einstein condensate rotating at close to the quadrupole instability frequency leads to turbulence with a Kolmogorov energy spectrum. The turbulent state is produced by energy transfer to condensate fragments that are ejected by the quadrupole instability. This energy transfer is driven by breaking the twofold rotational symmetry of the condensate. Subsequently, vortex-sound interactions damp the turbulent state leading to the crystallization of a vortex lattice.
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ItemDonor activation and damage in Si-SiO2 from low-dose, low-energy ion implantation studied via electrical transport in MOSFETsMcCamey, DR ; Francis, M ; McCallum, JC ; Hamilton, R ; Greentree, AD ; Clark, RG (IOP PUBLISHING LTD, 2005-05)
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ItemControlled shallow single-ion implantation in silicon using an active substrate for sub-20-keV ionsJamieson, DN ; Yang, C ; Hopf, T ; Hearne, SM ; Pakes, CI ; Prawer, S ; Mitic, M ; Gauja, E ; Andresen, SE ; Hudson, FE ; Dzurak, AS ; Clark, RG (AMER INST PHYSICS, 2005-05-16)We demonstrate a method for the controlled implantation of single ions into a silicon substrate with energy of sub-20-keV. The method is based on the collection of electron-hole pairs generated in the substrate by the impact of a single ion. We have used the method to implant single 14-keV P31 ions through nanoscale masks into silicon as a route to the fabrication of devices based on single donors in silicon.
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ItemIon-beam-assisted lift-off technique for three-dimensional micromachining of freestanding single-crystal diamondOlivero, P ; Rubanov, S ; Reichart, P ; Gibson, BC ; Huntington, ST ; Rabeau, J ; Greentree, AD ; Salzman, J ; Moore, D ; Jamieson, DN ; Prawer, S (WILEY-V C H VERLAG GMBH, 2005-10-17)