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Showing 1 to 20 of 26 for “"Thouless"”.
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Likelihood Theory and Methods for Generalized Linear Mixed Models
… designs. Towards the end of this thesis, a Thouless-Anderson-Palmer approach is introduced for modern statistical inference for generalized linear mixed models. Such methods have proven to provide accurate approximations to problems arising in machine learning contexts. However, statistical …
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A study of religious involvement among university students : literal, anti-literal, and mythological religious involvement
… measures: (i) Background variables; (ii) Thouless (1935): Intensity of Belief Scale; (iii) Rokeach (1960): Dogmatism Scale; (iv) 16 PF by Cattell et al. (1970) and (v) King and Hunt (1972 b): Scales for Basic Religious Dimensions. Hunt's notion that pro-religious subjects of different …
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Estudo de materiais magnéticos de baixa dimensionalidade dopados com impurezas não magnéticas
… temperatura de transição de fase de Kosterlitz-Thouless.
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Inhomogeneous 1H NMR spin-lattice relaxation in the organic superconductor κ-(BEDT-TTF)2-Cu[N(CN)2]Br
… on the phase. At Tc, they undergo a Kosterlitz-Thouless unbinding transition; the unbound vortices destroy long-range phase coherence. Previously reported proton NMR measurements on this material have shown a high sensitivity to vortex motion, but reported no interesting behavior above the phase …
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Numerical and Analytical Methods in Low-Dimensional Strongly Correlated Quantum Systems
… insulator, characterized by partly Kosterlitz-Thouless transition and partly Ising transition, is analyzed using both analytical renormalization group calculations and numerical density matrix renormalization group simulations. Additionally, the thesis introduces a statistical smoothing spline …
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On the Typical and Average Contributions to the Persistent Current in Mesoscopic Rings
… and comparable in magnitude per ring to the Thouless scale E<sub>c</sub> of energy level correlations. Taken in conjunction with earlier experiments, the new data strongly challenge conventional theories of the persistent current.
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Measurements of Vortex Diffusivity in 2d Superfluid Helium-4
… at temperatures well below the Kosterlitz-Thouless superfluid transition temperature. Our studies are with films of coverage .25 < (sigma)(,s) < 1.9 superfluid atomic layers and with .55 < T(,KT) < 1.9(DEGREES)K. We use a third sound resonator combined with a new detection technique('17) …
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Superfluid Density Measurements of High-Temperature Superconducting Films
… that is approximately described by a Kosterlitz-Thouless-Berezinskii (KTB) transition. However, in Bi-2212 films near optimal and critical doping, we find evidence for 3D-XY static and dynamic fluctuations. The dynamic critical exponent, z, in thin optimally-doped Bi-2212 films is directly …
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Two-dimensional superconducting states near zero temperature quantum phase transitions
… and demonstrate the existence of a Kosterlitz-Thouless (KT) transition in zero magnetic field. Applying a magnetic field to the sample, we have been able to observe the suppression of the superconducting response. Temperature sweeps in a magnetic field showed a similar discontinuity as observed …
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Implications of Vorticity and Disorder on Quantum Transport in Topological Semimetals
… computing clusters, we study the scaling of the Thouless conductance and Kubo conductivity in the presence of scalar and vector disorder. The results reveal distinct localization–delocalization behavior depending on the type of disorder and the tilt of the Dirac cone. In particular, we identify …
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Sound Waves and Turbulence in Two-dimensional Bose Gases
… of the gas close to the Berezinskii-Kosterlitz-Thouless (BKT) phase transition, while in the second one we study the out-of-equilibrium dynamics of the system. Our experiments are performed using a gas of $^{39}$K atoms confined in a 2D box trap, which guarantees the homogeneous gas density and …
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Non-Abelian Anyons in the Kitaev Honeycomb Model
… discussion about a numerical approach. Later on Thouless’ representation of the ground state is introduced to calculate the Berry phase. All these theoretical tools are applied to a 4 vortex configuration of the model to calculate the non-Abelian Berry phase of the system on a particular path in …
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Ponto crítico quântico supercondutor em sistemas multi-bandas
… the one-band case reduces to the one obtained by Thouless. We associate the emergence of superconductivity with the divergence of the static part of the generalized susceptibility. The advantage of this method is its simplicity, because we only deal with single-particle propagators. We analyze …
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Experimental study of the spin-glass phase diagram
… The observed behavior agrees with the de Almeida-Thouless instability line predicted by mean-field theory. This line does not represent a phase transition, but instead marks a crossover from short to long relaxation times in the spin-glass phase. The presence of weak random anisotropy in CuMn4 at. …
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Magnetic properties of transition metal dichloride - graphite intercalation compounds
… detail. Some of the predictions for a Kosterlitz-Thouless type transition are met in this compound, at least qualitatively , including an apparent jump in the spin stiffness at the critical point and a diffusive central peak in the scattering function originating from vortex autocorrelations. …
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Superfluidity in a uniform two-dimensional Bose gas
… as described by the Berezinskii-Kosterlitz-Thouless (BKT) theory, rather than the emergence of true long-range order. One of the most well-known features of BKT superfluidity is the universal jump in its superfluid density at a critical temperature without any discontinuities in the fluid’s …
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Mesoscopic quantum interference experiments in InGaAs and GaAs two-dimensional systems
… amplitude of the oscillations indicates that the Thouless energy forms the measure of excitation energies giving quantum decoherence. An in-plane magnetic field was applied to the single ring interferometer to study the Berry's phase and the Aharonov-Casher effect. The ring interferometer array …
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Imaging vortex dynamics in Josephson arrays using magnetic force microscopy
… films, as well as the Berezinkskii-Kosterlitz-Thouless phase transition in superconducting films[12]. Unconventional forms of superconductivity, such as the spin triplet pairing predicted in Sr2RuO4, or in topological insulators paired to s-wave superconductors, contain two condensates that may …
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Non-perturbative approaches to strongly correlated electron systems
… phase transition has the Berezinski-Kosterlitz-Thouless characteristic and the dynamical critical exponent can change across the quantum critical point. In chapter 5, we construct a gravity dual of the nematic phase by studying the condensation of a spin-two field in the Schwarzschild-AdS …
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Holography and strongly correlated systems
… phase transition of the Berezinskii-Kosterlitz-Thouless type. We study this transition in detail, revealing novel critical behavior, including locally quantum critical dynamics and the existence of an infinite tower of excited states related by a discrete subgroup of the original emergent …
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