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Related papers: Multi-band Wigner Function Formulation of Quantum …

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The Wigner function, which provides a phase-space description of quantum systems, has various applications in quantum mechanics, quantum kinetic theory, quantum optics, radiation transport and others. The concept of Wigner function has been…

High Energy Physics - Theory · Physics 2013-04-05 Stanislaw Mrowczynski

By making decomposition of the Wigner function simultaneously in both the spinor and the isospin spaces we derive a set of kinetic equations for the quark distribution functions and the spin densities. A detailed analysis of the…

High Energy Physics - Phenomenology · Physics 2009-10-30 Wojciech Florkowski

The formalism based on the equal-time Wigner function of the two-point correlation function for a quantized Klein--Gordon field is presented. The notion of the gauge-invariant Wigner transform is introduced and equations for the…

High Energy Physics - Phenomenology · Physics 2009-10-22 C. Best , P. Gornicki , W. Greiner

We describe microscopic theory for the quantum transport through finite interacting systems connected to noninteracting leads. It can be applied to small systems such as quantum dots, quantum wires, atomic chain, molecule, and so forth. The…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Akira Oguri

This review deals with the nonequilibrium Green's function (NEGF) method applied to the problems of energy transport due to atomic vibrations (phonons), primarily for small junction systems. We present a pedagogical introduction to the…

Mesoscale and Nanoscale Physics · Physics 2013-05-28 Jian-Sheng Wang , Bijay Kumar Agarwalla , Huanan Li , Juzar Thingna

In this paper we present theoretical studies of spin dependent transport in Fe/Cr/MgO/Fe tunnel junctions with non-collinear alignment of magnetizations of metallic layers comprising these MTJs. Calculations are performed with use of…

Mesoscale and Nanoscale Physics · Physics 2016-09-08 A. Vedyaev , N. Ryzhanova , N. Strelkov , M. Chshiev , L. Lystseva , B. Dieny

Electron transport properties in nanostructures can be modeled, for example, by using the semiclassical Wigner formalism or the quantum mechanical Green's functions formalism. We compare the performance and the results of these methods in…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Paula Havu , Noora Tuomisto , Riikka Vaananen , Martti J. Puska , Risto M. Nieminen

Using the superfield nonequilibrium Greens function technique, we derive the spatio-temporal spin magnetization quantum transport equations (SMQTEs) for a two-band model of semiconductors. The relevant variables are the real (Pauli-Dirac)…

Other Condensed Matter · Physics 2012-07-31 Felix A. Buot

We present a scheme for calculating coherent electron transport in atomic-scale contacts. The method combines a formally exact Green's function formalism with a mean-field description of the electronic structure based on the Kohn-Sham…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 K. S. Thygesen , K. W. Jacobsen

In this thesis we showed that Non-equilibrium Green's Function Perturbation Theory (NEGF) is really the overarching perturbative transport theory. This is shown in great detail by using NEGF as a starting point and developing in 3…

Mesoscale and Nanoscale Physics · Physics 2013-02-05 Meng Lee Leek

By viewing the non-equilibrium transport setup as a quantum open system, we propose a reduced-density-matrix based quantum transport formalism. At the level of self-consistent Born approximation, it can precisely account for the correlation…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Ping Cui , Xin-Qi Li , Jiushu Shao , YiJing Yan

The equation of motion for the reduced Wigner function of a system coupled to an external quantum system is presented for the specific case when the external quantum system can be modeled as a set of harmonic oscillators. The result is…

Quantum Gases · Physics 2017-05-11 Dries Sels , Fons Brosens

A generalized quantum kinetic equation (RKE) of the Kadanoff-Baym type is obtained on the basis of the Heisenberg equations of motion where the time evolution and space translation are separated from each other by means of the covariant…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. A. Smolyansky , A. V. Prozorkevich , G. Maino , S. G. Mashnik

Gradient expansions in quantum transport equations of a Kadanoff-Baym form have been reexamined. We have realized that in a consistent approach the expansion should be performed also inside of the self-energy in the scattering integrals of…

Statistical Mechanics · Physics 2009-10-28 Petr Král

For a quantum many-body system, the direct population of states of double-excitation character is a clear indication that correlations importantly contribute to its nonequilibrium properties. We analyze such correlation-induced transitions…

Strongly Correlated Electrons · Physics 2012-06-25 K. Balzer , S. Hermanns , M. Bonitz

We consider a quantum dot, affected by a local vibrational mode and contacted to macroscopic leads, in the non-equilibrium steady-state regime. We apply a variational Lang-Firsov transformation and solve the equations of motion of the Green…

Strongly Correlated Electrons · Physics 2015-05-28 T. Koch , J. Loos , A. Alvermann , H. Fehske

A single-time quantum transport equation, which includes effects beyond the quasiparticle approximation, is derived for Fermi-systems in the framework of non-equilibrium real-time Green's functions theory. Ternary correlations are…

Nuclear Theory · Physics 2009-10-30 A. Sedrakian , G. Roepke

The transport and gain properties of quantum cascade (QC) structures are investigated using a nonequilibrium Green's function (NGF) theory which includes quantum effects beyond a Boltzmann transport description. In the NGF theory, we…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 S. -C. Lee , A. Wacker

This paper is the documentation for a numerical code for quantum transport called KNIT. The KNIT library implements a generalization of the well known recursive Green function technique for a large class of multi-terminal mesoscopic systems…

Mesoscale and Nanoscale Physics · Physics 2010-10-14 Irina Rychkova , Valentin Rychkov , Kyryl Kazymyrenko , Simone Borlenghi , Xavier Waintal

Electronic transport in narrow gap semiconductors is characterized by spontaneous vertical transitions between carriers in the valence and conduction bands, a phenomenon also known as Zener tunneling. However, this effect is not captured by…

Materials Science · Physics 2021-04-21 Andrea Cepellotti , Boris Kozinsky