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Academic Commons Search Resultsen-usPerturbative and Nonperturbative Aspects of Jet Quenching in Near-Critical Quark-Gluon Plasmas
http://academiccommons.columbia.edu/catalog/ac:193924
Xu, Jiechenhttp://dx.doi.org/10.7916/D84Q7TSDWed, 27 Jan 2016 00:00:00 +0000In this thesis, we construct two QCD based energy loss models to perform quantitative analysis of jet quenching observables in ultra-relativistic nucleus-nucleus collisions at RHIC and the LHC. We first build up a perturbative QCD based CUJET2.0 jet flavor tomography model that couples the dynamical running coupling DGLV opacity series to bulk data constrained relativistic viscous hydrodynamic backgrounds. It solves the strong heavy quark energy loss puzzle at RHIC and explains the surprising transparency of the quark-gluon plasma (QGP) at the LHC. The observed azimuthal anisotropy of hard leading hadrons requires a path dependent jet-medium coupling in CUJET2.0 that implies physics of nonperturbative origin. To explore the nonperturbative chromo-electric and chromo-magnetic structure of the strongly-coupled QGP through jet probes, we build up a new CUJET3.0 framework that includes in CUJET2.0 both Polyakov loop suppressed semi-QGP chromo-electric charges and emergent chromo-magnetic monopoles in the critical transition regime. CUJET3.0 quantitatively describes the anisotropic hadron suppression at RHIC and the LHC. More significantly, it provides a robust connection between the long wavelength "perfect fluidity'' of the QGP and the short distance jet transport in the QGP. This framework paves the way for ``measuring'' both perturbative and nonperturbative properties of the QGP, and more importantly for probing color confinement through jet quenching.Physics, Nuclear physics, Particle physics, Quantum physics, Quark-gluon plasma, Scattering (Physics), Nuclear reactions, Nuclear physics, Color confinement (Nuclear physics), Quantum chromodynamicsjx2179PhysicsDissertationsSpectroscopy of Two Dimensional Electron Systems Comprising Exotic Quasiparticles
http://academiccommons.columbia.edu/catalog/ac:143043
Rhone, Trevor David Nathanielhttp://hdl.handle.net/10022/AC:P:12155Tue, 10 Jan 2012 00:00:00 +0000In this dissertation I present inelastic and elastic light scattering studies of collective states emerging from interactions in electron systems confined to two dimensions. These studies span the first, second and third Landau levels. I report for the first time, high energy excitations of composite fermions in the quantum fluid at v = 1/3. The high energies discovered represent excitations across multiple composite fermion energy levels, demonstrating the topological robustness of the fractional quantum Hall state at v = 1/3. This study sets the ground work for similar measurements of states in the second Landau level, such as those at v = 5/2. I present the first light scattering studies of low energy excitations of quantum fluids in the second Landau level. The study of low energy excitations of the quantum fluid at 3 ≥ v ≥ 5/2 reveals a rapid loss of spin polarization for v ≤ 3, as monitored by the intensity of the spin wave excitation at the Zeeman energy. The emergence of a continuum of low-lying excitations for v ≤ 3 reveals competing quantum phases in the second Landau level with intriguing roles of spin degrees of freedom and phase inhomogeneity. The first light scattering studies of the electron systems in the third Landau level are reported here. Measurements of low energy excitations and their spin degrees of freedom reveal contrasting behavior of states in the second and third Landau levels. I discuss these measurements in the context of the charge density wave phases, that are believed, by some, to dominate the third Landau level, and suggest ways of verifying this belief using light scattering. Distinct behavior in the dispersion of the spin wave at v = 3 is measured for the first time. The study may highlight differences in the first and second Landau levels that are manifested through the electron wavefunctions. In addition to intra-Landau level measurements, inter-Landau level studies are also reported. The results of which reveal roles of spin degrees of freedom and many body interactions in odd denominator integer quantum Hall states.Condensed matter physics, Optics, Quantum physicstnr2103Applied Physics and Applied Mathematics, PhysicsDissertations