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Showing 1 to 16 of 16 for “"Kosterlitz-Thouless"”.
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Estudo de materiais magnéticos de baixa dimensionalidade dopados com impurezas não magnéticas
… redução na 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
… effect 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 …
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Numerical and Analytical Methods in Low-Dimensional Strongly Correlated Quantum Systems
… density wave 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 …
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Measurements of Vortex Diffusivity in 2d Superfluid Helium-4
… flow dissipation 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 …
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Superfluid Density Measurements of High-Temperature Superconducting Films
… density 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 …
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Two-dimensional superconducting states near zero temperature quantum phase transitions
… temperature 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 …
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Sound Waves and Turbulence in Two-dimensional Bose Gases
… properties 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 …
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Magnetic properties of transition metal dichloride - graphite intercalation compounds
… in 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 …
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Superfluidity in a uniform two-dimensional Bose gas
… circulation 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 …
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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 …
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Non-perturbative approaches to strongly correlated electron systems
… the quantum 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 …
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Holography and strongly correlated systems
… in a quantum 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 …
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Two-Dimensional Discrete Gaussian Model at High Temperature
The Discrete Gaussian model is a Gaussian free field on lattice restricted to take integer values. In dimension two, it was proved by the seminal work of Fröhlich-Spencer that the Discrete Gaussian model exhibits localisation-delocalisation phase transition. The phase transition is ubiquitous in …
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Measurements of vortex diffusivity in 2D superfluid 4He
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-02T16:33:20Z No. of bitstreams: 1 1987_Volz.pdf: 1786717 bytes, checksum: 1cc26e52df659ca7f06b9deb99151dd8 (MD5)
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Nonlinear dissipation in two-dimensional helium films
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T13:40:58Z No. of bitstreams: 1 1982_buck.pdf: 4584541 bytes, checksum: 63f3eb8b668e1f21150f950fd563ce67 (MD5)
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Proximity effects and vortex dynamics in mesoscopic superconductor-normal metal-superconductor arrays
"Anderson's scaling theory of localization has proven invaluable in characterizing the behavior of real systems, that is, those possessing any amount of disorder. The theory predicts that, at zero temperature in 1D and 2D systems, the diffusive motion of electrons scattering off impurities ceases, …