An important object of study in harmonic analysis is the heat equation. On a Euclidean space, the fundamental solution of the associated semigroup is known as the heat kernel, which is also the law of Brownian motion. Similar statements also hold in the case of a Lie group. By using the wrapping map of Dooley and ildberger, we show how to wrap a Brownian motion to a compact Lie group from its Lie algebra (viewed as a Euclidean space) and find the heat kernel. This is achieved by considering It??o type stochastic differential equations and applying the Feynman-Ka??c theorem. We also consider wrapping Brownian motion to various symmetric spaces, where a global generalisation of Rouvi`ere???s formula and the e-function are considered. Additionally, we extend some of our results to complex Lie groups, and certain non-compact symmetric spaces.

Thesis (M.S.)--State University of New York at Binghamton, Department of Chemistry, 2006. / Includes bibliographical references.

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Understanding dynamics of colloidal dispersions is important for several applications ranging from coatings such as paints to growing colloidal crystals for photonic bandgap materials. The research outlined in this dissertation describes the use of Monte Carlo and Stokesian Dynamic simulations to model colloidal dispersions, and the development of theoretical expressions to quantify and predict dynamics of colloidal dispersions. The emphasis is on accurately modeling conservative, Brownian, and hydrodynamic forces to model dynamics of colloidal dispersions. In addition, we develop theoretical expressions for quantifying self-diffusion in colloids interacting via different particle-particle and particle-wall potentials. Specifically, we have used simulations to quantitatively explain the observation of anomalous attraction between like-charged colloids, develop a new criterion for percolation in attractive colloidal fluids, and validate the use of analytical expressions for quantifying diffusion in interfacial colloidal fluids. The results of this work contribute to understanding dynamics in interfacial and bulk colloidal fluids.

published_or_final_version / Mathematics / Doctoral / Doctor of Philosophy

In this thesis, we report a novel symmetry breaking system in single-beam optical trap. The breaking of symmetry is observed in Brownian dynamics of a linked pair of beads with substantially differing radii (500nm and 100nm). Such composite beads were originally conceived as a manipulation means to study of Brownian interactions between mesoscopic biological agents of the order of 100 – 200 nm (viruses or bacteria) with cell surfaces. During the initial testing of the composite bead system, we discovered that the system displayed thermally activated transitions and energetics of symmetry breaking. This thesis, while making a brief overview of the biological relevance of the composite bead system, focuses primarily on the analysis and experimentation that reveals the complex dynamics observed in the system. First, we theoretically analyze the origin of the observed symmetry breaking using electromagnetic theory under both Gaussian beam approximation and full Debye-type integral representation. The theory predicts that attachment of a small particle to a trapped microsphere results in creation of a bistable rotational potential with thermally activated transitions. The theoretical results are then verified using optical trapping experiments. We first quantify the top-down symmetry breaking based on measurement of the kinetic transition rates. The rotational potential is then explored using an experiment employing a novel algorithm to track rotational state of the composite bead. The results of the theory and experiments are compared with results of a Brownian dynamics simulation based on Smart Monte Carlo algorithm.

published_or_final_version / Statistics / Doctoral / Doctor of Philosophy

No description available.

An important object of study in harmonic analysis is the heat equation. On a Euclidean space, the fundamental solution of the associated semigroup is known as the heat kernel, which is also the law of Brownian motion. Similar statements also hold in the case of a Lie group. By using the wrapping map of Dooley and ildberger, we show how to wrap a Brownian motion to a compact Lie group from its Lie algebra (viewed as a Euclidean space) and find the heat kernel. This is achieved by considering It??o type stochastic differential equations and applying the Feynman-Ka??c theorem. We also consider wrapping Brownian motion to various symmetric spaces, where a global generalisation of Rouvi`ere???s formula and the e-function are considered. Additionally, we extend some of our results to complex Lie groups, and certain non-compact symmetric spaces.

Thesis (Ph. D.)--University of North Texas, Aug., 2007. / Title from title page display. Includes bibliographical references.