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We study theoretically the current-voltage characteristics, shot noise, and full counting statistics of a quantum wire double barrier structure. We model each wire segment by a spinless Luttinger liquid. Within the sequential tunneling…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Jaeuk U. Kim , Mahn-Soo Choi , Ilya V. Krive , Jari M. Kinaret

We present a theory for the frequency-dependent current fluctuations in superconducting quantum point-contacts (SQPC) within the dc transport regime. This theory is valid for any barrier transparency between the tunnel and ballistic limits,…

Condensed Matter · Physics 2009-10-28 A. Martin-Rodero , A. Levy Yeyati , F. J. Garcia-Vidal

We compute the current and the noise power matrix in a quantum dot connected to two metallic reservoirs by using the Keldysh field theory approach, a non-equilibrium quantum field theory language in the functional integral formalism. We…

Mesoscale and Nanoscale Physics · Physics 2024-11-20 Marco Uguccioni , Luca Dell'Anna

We study non-equilibrium noise in the transmission current through barriers in 1-D Luttinger liquids and in the tunneling current between edges of fractional quantum Hall liquids. The distribution of tunneling events through narrow barriers…

Condensed Matter · Physics 2009-10-22 C. de C. Chamon , D. E. Freed , X. G. Wen

Perpendicular magnetic tunnel junctions based on MgO/CoFeB structures are of particular interest for magnetic random-access memories because of their excellent thermal stability, scaling potential, and power dissipation. However, the major…

We investigate the spin Seebeck effect and spin pumping in a junction between a ferromagnetic insulator and a magnetic impurity deposited on a normal metal. By the numerical renormalization group calculation, we show that spin current is…

Mesoscale and Nanoscale Physics · Physics 2021-09-15 Tsuyoshi Yamamoto , Takeo Kato , Mamoru Matsuo

We analyze the influence of noise on magnetic properties of a su- perconducting loop which contains three Josephson junctions. This circuit is a classical analog of a persistent current (flux) qubit. A loop supercurrent induced by external…

Superconductivity · Physics 2009-11-13 E. Il'ichev , A. N. Omelyanchouk

We present a study of the magnetic dynamics associated with nanosecond scale magnetic switching driven by the spin Hall effect in 3-terminal nanoscale magnetic tunnel junctions (3T-MTJs) with in-plane magnetization. Utilizing fast pulse…

Mesoscale and Nanoscale Physics · Physics 2017-04-05 Graham E. Rowlands , Sriharsha V. Aradhya , Shengjie Shi , Erin H. Yandel , Junseok Oh , Daniel C. Ralph , Robert A. Buhrman

We study the spin dynamics in Fe|MgO|Fe tunnel junction with the dynamical exchange coupling by coupled Landau-Lifshitz-Gilbert equations. The effects of spin pumping on the spin dynamics are investigated in detail. It is observed that the…

Computational Physics · Physics 2018-07-23 Zhengren Yan , Xingtao Jia , Pingping Wu , Minghui Qin

A single-domain nanomagnet, shaped like a thin elliptical disk with small eccentricity, has a double well potential profile with two degenerate energy minima separated by a small barrier of a few kT (k = Boltzmann constant and T = absolute…

Mesoscale and Nanoscale Physics · Physics 2024-07-24 Rahnuma Rahman , Supriyo Bandyopadhyay

We analyze the precision of currents in a generic multi-terminal quantum-transport setting. Employing scattering theory, we show that the precision of the currents is limited by a function of the particle-current noise that can be…

Mesoscale and Nanoscale Physics · Physics 2025-07-14 Didrik Palmqvist , Ludovico Tesser , Janine Splettstoesser

Current fluctuations can provide additional insight into quantum transport in mesoscopic systems. The present work is carried out for the fluctuation properties of transport through a pair of coupled quantum dots which are connected with…

Mesoscale and Nanoscale Physics · Physics 2009-09-02 JunYan Luo , Xin-Qi Li , YiJing Yan

We show experimentally through time-resolved conductance measurements that magnetization reversal through domain wall motion in sub-100 nm diameter magnetic tunnel junctions is dominated by two distinct stochastic effects. The first…

A quantum statistical theory of spin-dependent tunneling through asymmetric magnetic double barrier junctions is presented which describes $both$ ballistic and diffuse tunneling by a single analytical expression. It is evidenced that the…

Materials Science · Physics 2009-11-07 M. Chshiev , D. Stoeffler , A. Vedyayev , K. Ounadjela

We study a frequency-dependent noise-to-current ratio for asymmetric, symmetric, and noncommutative current-noise in a ferromagnetic insulating junction, and extract quantum-mechanical properties of magnon transport at low temperatures. We…

Mesoscale and Nanoscale Physics · Physics 2019-04-04 Kouki Nakata , Yuichi Ohnuma , Mamoru Matsuo

We use a previously proposed theory for the temperature dependence of tunneling magnetoresistance to shed light on ongoing efforts to optimize spin valves. First we show that a mechanism in which spin valve performance at finite…

Mesoscale and Nanoscale Physics · Physics 2014-09-11 Karin Everschor-Sitte , Matthias Sitte , Allan H. MacDonald

Tunneling time in attosecond and strong field experiments is one of the most controversial issues in today's research, because of its importance to the theory of time, the time operator and the time-energy uncertainty relation in quantum…

Atomic Physics · Physics 2015-11-18 Ossama Kullie

Stochastic oscillators based on emerging nanodevices are attractive because of their ultra-low power requirement and ability to exhibit stochastic resonance, a phenomenon where synchronization to weak input signals is enabled due to ambient…

Mesoscale and Nanoscale Physics · Physics 2024-06-19 Punyashloka Debashis , Aman K. Maskay , Pramey Upadhyaya , Zhihong Chen

We show that in the presence of ferromagnetic electronic reservoirs and spin-dependent tunnel couplings, molecular vibrations in nonmagnetic single molecular transistors induce an effective intramolecular exchange magnetic field. It…

Mesoscale and Nanoscale Physics · Physics 2015-07-29 S. Weiss , J. Brüggemann , M. Thorwart

We extend the Keldysh formulation to quantum spin systems and derive exact equations of motion. This allows us to explore the dynamics of single spins and of ferromagnets when these are inserted between superconducting leads. Several new…

Superconductivity · Physics 2009-11-10 Zohar Nussinov , Alexander Shnirman , Daniel P. Arovas , Alexander V. Balatsky , Jian-Xin Zhu
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