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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Symmetry breaking and directed transport of cold atoms in optical lattices

Goonasekera, Malika January 2005 (has links)
The central theme of this thesis is the directed transport of cold atoms in optical lattices. Several methods for producing such an outcome are proposed, experimentally realised and characterised, in both dissipative and non-dissipative regimes. Accordingly, this thesis may be thought to be composed of two parts. The first section reports results of directed transport in non-dissipative optical lattices, where we used the atom optics realisation of the delta-kicked rotor (DKR) as a model system. Initial experiments performed on this system showed evidence of dynamical localisation, the signature of quantum chaos, and we exploited the presence of the momentum boundary (a barrier to diffusion arising from the approximation of delta-kicks with finite width impulses) to produce asymmetric momentum diffusion. Breaking the DKR system symmetries produced directed diffusion due to chaotic dynamics alone. We observed directed transport in a spatially symmetric system whenever temporal symmetry was broken, and also when the spatial and temporal symmetry of the DKR were simultaneously broken. We also report the first experimental evidence for a 'double-DKR', where experiments performed using a kick sequence composed of closely spaced pairs of kicks instead of single kicks caused significant alterations in the observed behaviour of the kicked rotor system. The origin of this new behaviour was explained in the framework of kick-to-kick correlations and our results were found to be in excellent agreement with numerical simulations. The second part of this thesis describes the realisation of a Brownian ratchet in a 3D dissipative lattice, where fluctuations between different potential surfaces acted as the source of noise. These fluctuations were rectified by the application of a periodic, bi-harmonic driving force, which broke the temporal symmetry of the system. Both current reversal and stochastic resonance behaviour characteristic of a Brownian ratchet were observed.
2

Maximum confidence measurements

Croke, Sarah January 2007 (has links)
No description available.
3

Semi-classical and quantum Monte Carlo simulations in optical lattices

Winklbauer, Stephen Peter January 2004 (has links)
No description available.
4

Quantum optics with dynamic environments

Linington, Ian January 2007 (has links)
No description available.
5

Quantum information processing with single photons

Lim, Yuan Liang January 2005 (has links)
No description available.
6

Quantum optics with a single trapped ion

Powell, Hebe Francis January 2003 (has links)
No description available.
7

88Sr+ ion trapping techniques and technologies for quantum information processing

Brownnutt, Michael January 2007 (has links)
No description available.
8

NMR quantum information processing with para-hydrogen

Anwar, Muhammad Sabieh January 2004 (has links)
No description available.
9

Molecules in optical lattices

Holt, John Robert January 2004 (has links)
No description available.
10

Networked quantum information processing

Hutton, Alexander January 2004 (has links)
No description available.

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