Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 89 for “"Quasiparticles"”.
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Quasiparticles in Quantum Many-Body Systems
… the most striking property of hosting anyon quasiparticles having fractional charges and fractional statistics. Such phases were discovered with the remarkable experiment of the fractional quantum Hall effect and are drawing a lot of recognition. Realization of these phases on lattice systems …
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Light-Matter Interactions with Photonic Quasiparticles
… electromagnetic excitations in solids ("photonic quasiparticles"), whose strongly confined electromagnetic fields can interact strongly with matter. This thesis describes how the rules of light-matter interactions are altered when bound and free electrons interact with photonic quasiparticles, and …
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Vortices and Quasiparticles in Superconducting Microwave Resonators
… magnetic flux vortices and nonequilibrium quasiparticles which can significantly impact the performance of superconducting microwave resonant circuits and qubits at millikelvin temperatures. Quasiparticles result in excess loss, reducing resonator quality factors and qubit lifetimes. …
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Spectroscopy of Two Dimensional Electron Systems Comprising Exotic Quasiparticles
In 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 …
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Pyrochlore spin ice Dy2Ti2O7: Investigating a platform for magnetic monopolar quasiparticles
… emergent fractionalized magnetic monopole quasiparticles as a consequence of defects in the spin ice symmetry. This work sought to probe the existence, statics, and dynamics of these monopole quasiparticles, and what factors affect their density and mobility. At the beginning of study, …
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The Death of Quasiparticles: Strongly Interacting Gapless Phases with Fermi Surfaces and Fractional Statistics
The emergence of quasiparticles at low temperature provides a powerful organizing principle for many quantum phases of matter, ranging from conventional magnets and superconductors to exotic insulators with topological order. In this thesis, I describe my research in gapless quantum phases in which …
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Direct Observation of Nodal Quasiparticles In The Non-Magnetic Superconductors Y (LU) NI2B2C Via Field-Angle Dependent Heat Capacity
Submitted by Meng Tao (mengtao2@illinois.edu) on 2012-10-26T22:04:50Z No. of bitstreams: 1 Park.pdf: 2696883 bytes, checksum: 6ff229cbc1779fdf8a2c837b0f177b3b (MD5)
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Direct Observation of Nodal Quasiparticles in the Non-Magnetic Superconductors Yttrium(lutetium)nickel-Boron-Carbon Field-Angle Dependent Heat Capacity
… permitting electronic excitations, termed nodal quasiparticles, to exist at temperatures well below the superconducting transition. In the vortex phase, the presence of nodal quasiparticles should be directly observable through the variation of the heat capacity with the angle between a magnetic …
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Probing the Superconducting Gap of Lead With Ballistic Phonons
The assumption that quasiparticles are all in thermal equilibrium with the helium-bath leads to erroneous results for temperature dependences of phonon absorption. Instead, we assume that the phonon-imaging experiment creates small regions of raised temperature that contribute non-equilibrium …
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Quasiparticle and Phonon Transport in Superconducting Particle Detectors
… tunnel junctions to investigate the transport of quasiparticles and phonons in structures similar to the proposed detector designs. I have used multiple distributed junction geometries to perform injection-detection type experiments. One junction is used to inject quasiparticles and/or phonons …
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Low temperature quasiparticle transport in d-wave superconductors
… surface. Near each of these four gap nodes, quasiparticles are easily excited and behave more like massless relativistic particles than electrons in a metal. In this thesis, we study the transport properties of these nodal quasiparticles, providing theoretical interpretations for the results …
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Interacting Elementary Excitations in Ultrarelativistic Plasmas: Damping Mechanisms and Plasma Thermodynamics
… vary linearly with the excitation energy. The quasiparticles are therefore not as well- defined as those encountered in non-relativistic plasmas, with short-ranged interactions, where the variation of the damping rates away from the Fermi surface is quadratic, thus slower. Second, we find that …
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Phonon-quasiparticle interactions in dilute solutions of He3 in superfluid He4
… for phonon scattering and absorption by He3 quasiparticles as well as the effective interaction between quasiparticles are discussed from the microscopic theory. Much of the previous semiphenomonological theory concerning these quantities is justified. The properties of a dilute gas model for …
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Determing the Properties of Dense Matter: Superconductivity, Bulk Viscosity, and Light Reflection in Compact Stars
… We derive an effective theory of Cooper pair quasiparticles from a microscopic theory of nucleons, and calculate the coupling strengths between quasiparticles. We then calculate the structure of magnetic flux tubes, taking into consideration interactions between neutron and proton Cooper …
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Quantum liquid crystal phases and unconventional magnetism in electronic and atomic fermi systems
… an order-parameter theory coupled to fermionic quasiparticles. Both commensurate and incommensurate smectic (or stripe) cases are studied. Close to the quantum critical point (QCP), the spectrum of fluctuations of the nematic phase has low-energy fluctuating stripes. I study the quantum critical …
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Acoustic waves in crystals: I. Ultrasonic flux imaging and internal diffraction. II. Imaging phonons in superconducting niobium
… interesting interactions between phonons and quasiparticles.
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Hall effect in the superconducting and normal states in detwinned and twinned single crystals of zinc-doped yttrium barium copper oxide
… contribution, and the other term comes from the quasiparticles in the vortex cores.
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Nonzero temperatures and emergent disorder in spin liquids
… gauge fields, and the existence of exotic quasiparticles with fractional statistics. Meanwhile, at temperatures that are high compared to all characteristic interaction energy scales in the system, they often behave as trivial, uncorrelated paramagnets. This thesis aims to better understand …
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Majorana qubits in non-Abelian topological superconductors
… qubits and gates built from the Majorana quasiparticles. The main decoherence effects are the tunneling splitting of the topological degeneracy, thermal excitations and superconducting fluctuations which are not treated in the usual BCS mean-field theory. We calculate the tunneling …
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Interaction elementary excitations in ultrarelativistic plasmas: damping mechanisms and plasma thermodynamics
… vary linearly with the excitation energy. The quasiparticles are therefore not as well-defined as those encountered in non-relativistic plasmas, with short-ranged interactions, where the variation of the damping rates away from the Fermi surface is quadratic, thus slower. Second, we find that …
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