Masters Degrees (Physics)
https://researchspace.ukzn.ac.za/handle/10413/6604
Sat, 28 Nov 2020 07:27:14 GMT2020-11-28T07:27:14ZPhase transitions in induced lattice gauge models.
https://researchspace.ukzn.ac.za/handle/10413/18410
Phase transitions in induced lattice gauge models.
The present research is based on the study of the phase structure of lattice models incorporating selfinteracting scalars and gauge background fields otherwise known as induced gauge models. Emphasis is placed on the effect the choice of the integration measure over the radial modes of the scalar fields have on the phase structure of these models. Both numerical simulations and analytical results based on the mean field approximations are presented.
In Chapter 1 an introduction to quantum field theory is given leading to the formulation of Euclidean quantum field theory.
In Chapter 2 global and local gauge invariance together with the mechanism of spontaneous symmetry breaking are discussed.
In Chapter 3 the formulation of quantum field theory on the lattice is introduced. The lattice regularization entails discretizing space and time and presents an elegant approach to studying certain phenomena of the continuum theory which are beyond the reach of standard perturbative analysis.
In Chapter 4 the Monte Carlo methods for evaluating the Euclidean Feynman path integral as applied to lattice gauge theory are discussed.
In Chapter 5 numerical studies of some lattice gauge models are presented. Both pure lattice gauge models and gauge-Higgs models are examined.
In Chapter 6 the Kazakov-Migdal model which presents an interesting approach to inducing QCD is discussed.
In Chapter 7 the mixed fundamental-adjoint induced model is introduced. This model succeeds in breaking the local ZN symmetry of the Kazakov-Migdal model by adding to it scalar fields in the fundamental representation of the gauge group. The effect of the choice of the radial integration measure on the phase structure of a class of Abelian induced models is studied.
Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.
Sun, 01 Jan 1995 00:00:00 GMThttps://researchspace.ukzn.ac.za/handle/10413/184101995-01-01T00:00:00ZDigital control of light.
https://researchspace.ukzn.ac.za/handle/10413/18012
Digital control of light.
The objective of this research was to describe innovative ways in which digital holography
can be applied in controlling laser light. The ability to control and manipulate a laser beam
has become an extremely desirable feature since it enables improvement in the efficiency and
quality of a number of applications.
Methods of controlling light make use of optical components to change the properties of a
light beam according to the function of that optical element; therefore, a particular arrange-
ment of optical elements in a system controls light in a certain way.
Technological advancements in the field of optics have developed a versatile device called
a spatial light modulator (SLM), which is a novel instrument that employs computer gener-
ated holographic patterns (or phase masks) to modulate the amplitude and /or phase of a
laser beam and it can therefore perform the function of a number of optical elements.
This research presents novel optical set-ups based on the phase-only liquid crystal spatial
light modulator (LC-SLM) for generating, controlling and exploring different laser beam pat-
terns. The thesis has three main sections, the first one is Holographic beam shaping, where a
Gaussian beam was reshaped using an SLM to produce Vortex, Bessel or Laguerre-Gaussian
beams. These beams were found to agree with theoretically generated beams.
Secondly, we produce o -axis laser beams by constructing coherent superpositions of Gaussian
and vortex modes and then use two measurement techniques, peak intensity ratio and modal
decomposition technique, to obtain the constituent components of these fields.
Finally, we investigate the propagation dynamics of Vortex and Laguerre-Gaussian beams
by using a SLM to digitally propagate these beams in free space, and then perform mea-
surements on the far field intensity pattern. The results show that the Laguerre-Gaussian
beam suffers less spreading and beam distortion compared to the vortex beam in free space
propagation.
Masters Degree. University of KwaZulu-Natal, Pietermaritzburg.
Tue, 01 Jan 2019 00:00:00 GMThttps://researchspace.ukzn.ac.za/handle/10413/180122019-01-01T00:00:00ZMetallic nanoparticle-graphene quantum dot nanocomposites for the electrochemical detection of methyl parathion.
https://researchspace.ukzn.ac.za/handle/10413/17218
Metallic nanoparticle-graphene quantum dot nanocomposites for the electrochemical detection of methyl parathion.
Masters Degree. University of KwaZulu-Natal, Durban.
Sun, 01 Jan 2017 00:00:00 GMThttps://researchspace.ukzn.ac.za/handle/10413/172182017-01-01T00:00:00ZNon-reversal open quantum walks.
https://researchspace.ukzn.ac.za/handle/10413/17099
Non-reversal open quantum walks.
In this thesis, a new model of non-reversal quantum walk is proposed. In such a walk, the walker cannot go back to previously visited sites but it can stay static or move to a new site. The process is set up on a line using the formalism of Open Quantum
Walks (OQWs). Afterwards, non-reversal quantum trajectories are launched on a 2-D lattice to which a memory is associated to record visited sites. The “quantum coins” are procured from a randomly generated unitary matrix. The radius of spread of the
non-reversal OQW varies with di↵erent unitary matrices. The statistical results have meaningful interpretations in polymer physics. The number of steps of the trajectories is equivalent to the degree of polymerization, N. The root-mean-square of the radii
determines the end-to-end distance, R of a polymer. These two values being typically related by R ⇠ N⌫, the critical exponent, ⌫, is obtained for N 400. It is found to be closely equal to the Flory exponent. However, for larger N, the relationship does
not hold anymore. Hence, a di↵erent relationship between R and N is suggested.
Master of Science in Physics. University of KwaZulu Natal, Durban 2015.
Thu, 01 Jan 2015 00:00:00 GMThttps://researchspace.ukzn.ac.za/handle/10413/170992015-01-01T00:00:00Z