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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 24 for “"low-energy excitations"”.
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Low Energy Excitations of 1D Fermi Gases
… fermions using cold atom techniques and probe low-energy excitations in such systems. We do so using the technique of Bragg spectroscopy, which enables us to probe the dynamical structure factor of the system directly, which in turn tells us about the density-density and spin-density …
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Low-energy excitations in yttria-stabilized zirconia
… constant and thermal expansion measurements below 2 K on single crystal samples of Zr02 :Y203 with 10.5, 16 and 18 mole % Y2O3 contents exhibit properties typical of glasses. The presence of glass-like excitations having a broad spectrum of energies is indicated by the quadratic temperature …
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Glass-like, low-energy excitations in neutron-irradiated quartz
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-20T16:45:14Z No. of bitstreams: 1 1980_gardner.pdf: 2178585 bytes, checksum: 17af2ffa057ba97feb81bad4e9b375a0 (MD5)
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The effect of neutron irradiation on the density of low-energy excitations in vitreous silica
Systematic low-temperature measurements of the thermal conductivity, specific heat, dielectric constant, and temperature-dependent ultrasound velocity have been made on a single piece of vitreous silica. These measurements were repeated after fast neutron irradiation of the material. It was found …
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Universal conductance fluctuations, glassy kinetics, and 1/f noise
… universal conductance fluctuation theory in the low temperature regime. Statistical properties of the noise in these systems were also studied in specially fabricated nanometer scale samples. Non-Gaussian effects and other aspects of the noise in these samples were used to probe the kinetics of …
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Spectroscopy of Two Dimensional Electron Systems Comprising Exotic Quasiparticles
… 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 …
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Fermions at finite density in the nonrelativistic gauge/gravity duality
… an important quantity that controls the low-energy excitations of the theory, depends on the momentum along the "extra" direction in nonrelativistic gauge/gravity duality.
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Unconventional Fermi surface in insulating SmB6 and superconducting YBa2Cu3O6+x probed by high magnetic fields
… surface, the locus in momentum space of gapless low-energy excitations, is a concept of fundamental importance in solid state physics. Electronic properties of a material are determined by the long-lived low-energy excitations near the Fermi surface. Conventionally, Fermi surface is understood as …
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Magnetoresistance and Thermoelectricity in Quasi-Low Dimensional Semimetals
The emergent properties and low energy excitations of low dimensional condensed matter systems are profoundly affected by the interplay of strong magnetic field and the anisotropic ionic potential of the crystal lattice. Detailed information of the underlying physics of such systems can be probed …
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The structure of paired boson superfluids
… superfluid vortices using the Ginsburg Landau energy equation. Specifically, two types of superfluids are considered, ordinary superfluids where single bosons condense to form a strongly correlated system and superfluids where pairs of bosons condense to form a strongly correlated system while …
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Low Temperature Behavior of Potassium and Sodium-Silicate Glasses
The low-temperature properties of a system of well characterized potassium and sodium silicate glasses have been measured in an effort to better understand the nature of the low-energy excitations which exist in all glasses and to further investigate relationships between the low-temperature …
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An action principle for dissipative fluid dynamics
Fluid dynamics is the universal theory of low-energy excitations around equilibrium states, governing the physics of long-lived modes associated with conserved charges. Historically, fluid dynamics has been formulated at the level of equations of motion, in terms of a local fluid velocity and …
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Low temperature, glass-like properties of crystalline beta-alumina
The low temperature properties measured for single crystal Na, Ag, K, and Li B-alumina are characteristic of those found in amorphous materials. The specific heat is dominated below 1 K by a term approximately linear in temperature instead of the cubic dependence normal for crystals. All except K …
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On superradiant phase transitions in generalised Dicke models
… sets in. A superradiant phase develops for low temperatures or strong coupling between light and atoms, which is characterised by a macroscopic excitation of the light field and a spontaneous, collective polarisation of the atoms. This thesis discusses a generalised version of the Dicke …
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MONITORING PHONON DYNAMICS IN QUANTUM MATERIALS BY TIME-RESOLVED SPONTANEOUS RAMAN SCATTERING
… TRRS provides unique access to phonons and other low-energy excitations in systems impulsively driven into transient non-equilibrium states, allowing mode-specific monitoring of their population dynamics. This makes TRRS particularly powerful for investigating electron-phonon and phonon-phonon …
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Study of atomic tunneling centers in the mixed crystal KBr1̳-̳x̳(CN)x̳ using dielectric echo techniques
… wide range of behavior. In the dilute limit of low cyanide concentration, the CN molecules behave as isolated impurities in the ordered KBr host lattice. For cyanide concentrations of x(CN)~50%, however, disorder due to strong CN-CN interactions produces low-temperature properties that are …
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Quantized vortices in arbitrary dimensions and the normal-to-superfluid phase transition
The structure and energetics of superflow around quantized vortices, and the motion inherited by these vortices from this superflow, are explored in the general setting of a superfluid in arbitrary dimensions. The vortices may be idealized as objects of co-dimension two, such as one-dimensional …
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First principles study of structure, defects and proton insertion in MnO₂
… structures are found to be near degenerate in energy with pyrolusite, no thermal disorder exists in the system up to several thousand degrees as the strong correlation of the Mn-vacancy order along the lines of face sharing octahedra removes any low-energy excitations from the system. …
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A Study of Atomic Tunneling Centers in the Mixed Crystal Potassium-Bromide(1-X)(cyanide)(x) Using Dielectric Echo Techniques
… wide range of behavior. In the dilute limit of low cyanide concentration, the CN molecules behave as isolated impurities in the ordered KBr host lattice. For cyanide concentrations of $x$(CN) $\approx$ 50%, however, disorder due to strong CN-CN interactions produces low-temperature properties …
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Low-energy, localized excitations in amorphous polymers
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-20T20:03:53Z No. of bitstreams: 1 1980_matsumoto.pdf: 4103014 bytes, checksum: 0ca927dd0f785f97fb48332794b75f28 (MD5)
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