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We derive the fluctuation theorem for a stochastic and periodically driven system coupled to two reservoirs with the aid of a master equation. We write down the cumulant generating functions for both the current and entropy production in…

Statistical Mechanics · Physics 2020-11-26 Kazutaka Takahashi , Yuki Hino , Keisuke Fujii , Hisao Hayakawa

Systems that are driven out of thermal equilibrium typically dissipate random quantities of energy on microscopic scales. Crooks fluctuation theorem relates the distribution of these random work costs with the corresponding distribution for…

Quantum Physics · Physics 2018-02-13 Johan Aberg

We explore how non-equilibrium noise affects spin-torque switching elements and oscillators. To do so we first discuss the deterministic dynamics of magnetic tunnel junctions, introducing a convenient set of slow and fast degrees of…

Mesoscale and Nanoscale Physics · Physics 2011-10-18 T. Dunn , A. L. Chudnovskiy , A. Kamenev

We determine the shot noise asymmetry of a quantum dot under reversal of an external magnetic field. The dot is coupled to edge states which invert their chirality when the field is reversed, leading to a magnetoasymmetric electrochemical…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 David Sanchez

Using the fluctuation theorem supplemented with geometric arguments, we derive universal features of the (long-time) efficiency fluctuations for thermal and isothermal machines operating under steady or periodic driving, close or far from…

Statistical Mechanics · Physics 2014-11-26 Gatien Verley , Tim Willaert , Christian Van den Broeck , Massimiliano Esposito

Using one of the methods of quantum nonequilibrium statistical physics we have investigated the spin transport transverse to the normal metal/ferromagnetic insulator interface in hybrid nanostructures. An approximation of the effective…

Mesoscale and Nanoscale Physics · Physics 2015-06-11 I. I. Lyapilin , M. S. Okorokov , V. V. Ustinov

We propose a method for inducing magnetization reversal using an AC spin current polarized perpendicular to the equilibrium magnetization of the free magnetic layer. We show that the critical AC spin current is significantly smaller than…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Tom Dunn , Alex Kamenev

The thermal activation of magnetization reversal in magnetic nanoparticles is controlled by the anisotropy-energy barrier. Using perturbation theory, exact diagonalization and stability analysis of the ferromagnetic spin-s Heisenberg model…

Mesoscale and Nanoscale Physics · Physics 2012-04-16 Mohammad Sayad , Daniel Gütersloh , Michael Potthoff

It is shown that under appropriate conditions spin-transfer-driven magnetization dynamics in a single-domain nanomagnet is conservative in nature and admits a specific integral of motion, which is reduced to the usual magnetic energy when…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 Giorgio Bertotti , Claudio Serpico , Isaak D. Mayergoyz

In this study the power flow in a coupled mechanical and electromagnetic harvesting system in presence of both positional and electrical fluctuations is analyzed. Explicit expressions for the power into and out of the mechanical and…

Classical Physics · Physics 2014-05-30 Lars Egil Helseth

Spin polarized current may transfer angular momentum to a ferromagnet, resulting in a spin-torque phenomenon. At the same time the shot noise, associated with the current, leads to a non-equilibrium stochastic force acting on the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 A. L. Chudnovskiy , J. Swiebodzinski , A. Kamenev

We perform 3D micromagnetic simulations of current-driven magnetization dynamics in nanoscale exchange biased spin-valves that take account of (i) back action of spin-transfer torque on the pinned layer, (ii) non-linear damping and (iii)…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 G. Siracusano , G. Finocchio , I. N. Krivorotov , L. Torres , G. Consolo , B. Azzerboni

A theoretical model is developed that can accurately analyze the effects of thermal fluctuations in antiferromagnetic (AFM) nano-particles. The approach is based on Fourier series representation of the random effective field with cut-off…

Mesoscale and Nanoscale Physics · Physics 2019-07-26 Yuriy G. Semenov , Xiniy Xu , Ki Wook Kim

In equilibrium, the fluctuation-dissipation theorem (FDT) expresses the response of an observable to a small perturbation by a correlation function of this variable with another one that is conjugate to the perturbation with respect to…

Statistical Mechanics · Physics 2010-10-13 Udo Seifert , Thomas Speck

Magnetization reversal in magnetic nanostructures is investigated numerically over time-scales ranging from fast switching processes on a picosecond scale to thermally activated reversal on a microsecond time-scale. A simulation of the…

Statistical Mechanics · Physics 2015-06-24 D. Hinzke , U. Nowak

We demonstrate that the fluctuation theorem of Gallavotti and Cohen can be used to characterize the class of dynamics that arises in nonthermal systems of collectively interacting particles driven over random quenched disorder. By observing…

Statistical Mechanics · Physics 2013-12-05 J. A. Drocco , C. J. Olson Reichhardt , C. Reichhardt

The miniaturisation of magnetic read heads and random access memory elements makes them vulnerable to thermal fluctuations. We demonstrate how current-induced spin-transfer torques can be used to suppress the effects of thermal…

Mesoscale and Nanoscale Physics · Physics 2011-03-07 Swarnali Bandopadhyay , Arne Brataas , Gerrit E. W. Bauer

The theory of current transport in a narrow superconducting channel accounting for thermal fluctuations is developed. These fluctuations result in the appearance of small but finite dissipation in the sample. The value of corresponding…

Superconductivity · Physics 2009-10-15 Yu. N. Ovchinnikov , A. A. Varlamov

The current theoretical and experimental situations are reviewed for low-dimensional insulating systems with a low magnetic transition temperature TM and pronounced short-range magnetic order above this temperature. Both the standard and…

Strongly Correlated Electrons · Physics 2007-09-18 A A Katanin , V Yu Irkhin

Spin fluctuation and transition have always been one of central topics of magnetism and condensed matter science. Experimentally, the spin fluctuation is found transcribed onto scattering intensity in the neutron scattering process, which…