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Related papers: Multifractal Magnetoconductance Fluctuations in Me…

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We study the off-diagonal current fluctuation in a macroscopic quantum system measured in an ideal manner that is as close as possible to the classical ideal measurement. We show rigorously that not only extended but also localized states…

Mesoscale and Nanoscale Physics · Physics 2022-02-02 Kentaro Kubo , Kenichi Asano , Akira Shimizu

Thermodynamic and transport properties of normal disordered conductors are strongly influenced by the proximity of a superconductor. A cooperation between mesoscopic coherence and Andreev scattering of particles from the superconductor…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 Alexander Altland , B D Simons , D Taras-Semchuk

We study fluctuations of the conductance of micron-sized graphene devices as a function of the Fermi energy and magnetic field. The fluctuations are studied in combination with analysis of weak localization which is determined by the same…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 D. W. Horsell , A. K. Savchenko , F. V. Tikhonenko , K. Kechedzhi , I. V. Lerner , V. I. Fal'ko

We perform scanning gate experiments on ballistic constrictions in the presence of small perpendicular magnetic fields. The constrictions form the entrance and exit of a circular gate-defined ballistic stadium. Close to constrictions we…

Mesoscale and Nanoscale Physics · Physics 2015-06-15 A. A. Kozikov , D. Weinmann , C. Roessler , T. Ihn , K. Ensslin , C. Reichl , W. Wegscheider

We calculate the conductance of quasi-one-dimensional nanowires with electronic states confined to a surface charge layer, in the presence of a uniform magnetic field. Two-terminal magnetoconductance (MC) between two leads deposited on the…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 Yaroslav Tserkovnyak , Bertrand I. Halperin

We first summarize our recent observations, through magnetization measurements in different low-Tc superconductors, of a rather sharp disappearance of the superconducting fluctuations in the normal state when the magnetic field approaches…

Superconductivity · Physics 2009-11-11 Manuel V. Ramallo , Jesus Mosqueira , Carlos Carballeira , Felix Soto , Felix Vidal

A model of a ferromagnet is considered, in which there arise mesoscopic fluctuations of paramagnetic phase. The presence of these fluctuations diminishes the magnetization of the ferromagnet, softens the spin-wave spectrum, increases the…

Statistical Mechanics · Physics 2015-06-25 V. I. Yukalov

A general theory of thermal magnetic fluctuations near conductive materials is developed; such fluctuations are the magnetic analog of Johnson noise. For realistic experiments in quantum computing and magnetic resonance force microscopy,…

Quantum Physics · Physics 2007-05-23 J. A. Sidles , J. L. Garbini , W. M. Dougherty , S. H. Chao

We investigate the transport properties of open quantum chaotic systems in the semiclassical limit. We show how the transmission spectrum, the conductance fluctuations, and their correlations are influenced by the underlying chaotic…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Ph. Jacquod , E. V. Sukhorukov

Quantum corrections to the electrical conduction of magnetic semiconductors are comparatively unexplored. We report measurements of time-dependent universal conductance fluctuations (TDUCF) and magnetic field dependent universal conductance…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. Lee , A. Trionfi , T. Schallenberg , H. Munekata , D. Natelson

Fluctuations in the return time statistics of a dynamical system can be described by a new spectrum of dimensions. Comparison with the usual multifractal analysis of measures is presented, and difference between the two corresponding sets…

Chaotic Dynamics · Physics 2009-11-07 N. Hadyn , J. Luevano , G. Mantica , S. Vaienti

We use a multifractal formalism to study the effect of stochastic resonance in a noisy bistable system driven by various input signals. To characterize the response of a stochastic bistable system we introduce a new measure based on the…

Chaotic Dynamics · Physics 2009-10-31 Alexander Silchenko , Chin-Kun Hu

We present an X-ray diffuse scattering study of the pretransitional structural fluctuations of the magneto-elastic transition in alpha'-NaV2O5. This transition is characterized by the appearance below Tsp~35K of satellite reflections at the…

Strongly Correlated Electrons · Physics 2009-10-31 S. Ravy , J. Jegoudez , A. Revcolevschi

Co nuclear-quadrupole-resonance (NQR) measurements were performed on various bilayered hydrate cobaltate Na_x(H_3O)_zCoO_2\cdot yH_2O with different values of the superconducting and magnetic-ordering temperatures, T_c and T_M,…

We analyze the dynamics of a charged particle moving in the presence of spatially-modulated magnetic fields. From Poincare surfaces of section and Liapunov exponents for characteristic trajectories we find that the fraction of pinned and…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Esmael Badran , Sergio E. Ulloa

We combine experiments and theory to investigate the dynamics and orientational fluctuations of ferromagnetic microellipsoids that form a ribbon-like structure due to attractive dipolar forces. When assembled in the ribbon, the ellipsoids…

Soft Condensed Matter · Physics 2017-07-26 Helena Massana-Cid , Fernando Martinez-Pedrero , Andrejs Cebers , Pietro Tierno

The famous Johnson-Nyquist formula relating noise current to conductance has a microscopic generalization relating noise current density to microscopic conductivity, with corollary relations governing noise in the components of the…

Computational Physics · Physics 2013-08-27 M. T. Homer Reid , Alejandro W. Rodriguez , Steven G. Johnson

The dilute Heisenberg ferromagnet is studied taking into account fluctuations of magnetization caused by disorder. A self-consistent system of equations for magnetization and its mean quadratic fluctuations is derived within the…

Condensed Matter · Physics 2015-06-25 I. Vakarchuk , V. Tkachuk , T. Kuliy

We study the density of states (DOS) and the transition temperature $T_c$ in a dirty superconducting film with rare classical magnetic impurities of an arbitrary strength described by the Poissonian statistics. We take into account that the…

Superconductivity · Physics 2018-01-24 I. S. Burmistrov , M. A. Skvortsov

Macroscopic systems often display phase transitions where certain physical quantities are singular or self-similar at different (spatial) scales. Such properties of systems are currently characterized by some order parameters and a few…

Statistical Mechanics · Physics 2013-04-12 Zhi Chen , Xiao Xu