Browsing by Author "Adams, Rory Montague"

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    Flux corrected transport applied to hydrodynamics for heavy ion collisions
    (2008) Adams, Rory Montague; Cleymans, Jean; Muronga, Azwinndini
    This thesis presents FCTHydro, a ROOT package, and its application to hydrodynamic simulations through the packages RelHydro and Nonideal xy. These packages aim to provide the broader heavy ion collision community with access to hydrodynamic simulation software which is now accessible from within the primary analysis framework, ROOT. Tests are performed and show how well the high-order, monotone, conservative, positivity preserving routines within FCTHydro simulate hydrodynamic systems with harsh initial conditions. RelHydro illustrates the application of FCTHydro to relativistic systems and Nonideal xy the application to causal non-ideal hydrodynamic systems. Nonideal xy is also used to obtain a first order understanding of the effects of the relaxation times in causal non-ideal hydrodynamics. In addition, a semi-analytic solution for the particle rapidity spectra obtained by combining Landau hydrodynamics and the Cooper-Frye freezeout formalism is given. The results are compared with the Landau Gaussian and a known approximation for midrapidies. The Landau Gaussian provides the best approximation to experimental data. Furthermore, the chemical freezeout results for preliminary data from AGS for central Au-Au collisions at nominal beam energies 2, 4, 6 and 8 AGeV are shown to agree with the E/N = 1 GeV freezeout criteria. These data allow access to a previously unexplored region in the T-μB phase space.
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    Zero modes and degrees of freedom of topological solitons on the plane
    (2003) Adams, Rory Montague; Barashenkov, I V
    In this thesis we analyse the coaxial multivortices of the Ginzburg-Landau, the Euclidean complex sine-Gordon-1 and -2 theories on the plane. More specifically, we determine the number of continuous free parameters describing the largest family of solutions, with these vortices as members. This is accomplished by obtaining the zero modes of the vortices. For the Ginzburg-Landau model we show that the multivortices do not belong to a larger family of solutions and only depend on parameters describing their global U(1) symmetry and translations in the plane. Thus it is not possible to continuously deform these coaxial multivortices into a system of multiple, separated vortices. In contrast, the multivortices of complex sine-Gordon-1 model are shown to have an infinite number of zero modes and can be continuously deformed into a configuration of multiple, separated vortices. We also show that the largest family of solutions, with these coaxial multivortices as members, is a recently discovered family describing non-coaxial multivortices. For the complex sine-Gordon-2, we show the coaxial multivortices belong to a larger family of solutions which depend on a finite number of continuous free parameters. We also speculate as to the form of solutions that this larger family can describe.