Sökning: "Greens function"

Visar resultat 6 - 10 av 76 avhandlingar innehållade orden Greens function.

  1. 6. Analytical and Numerical Developments in Strongly Correlated Systems: Perspectives from TDDFT and Green's Functions

    Författare :Daniel Karlsson; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Many-Body Perturbation Theory; Hubbard model; TDDFT; Green s function; DFT; Quantum Transport; Disorder; Fysicumarkivet A:2014:Karlsson;

    Sammanfattning : This thesis investigates different methods for treating strongly correlated systems, and discusses their respective strengths and weaknesses. Many of the results presented in this thesis come from comparing the different methods and approximations to exact results. LÄS MER

  3. 7. Surface energetics from one-electron Green's function theory

    Författare :Magnus Aldén; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : .... LÄS MER

  4. 8. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

    Författare :Victor Dykin; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; BWR and PWR stability; stability indicators; propagating density perturbation; autocorrelation function; density wave oscillations; decay ratio; non-white driving force; damped harmonic oscillator; reduced order models; Green s function technique;

    Sammanfattning : Neutron noise analysis techniques are studied and developed, with primary useof determining the stability of Boiling Water Reactors (BWRs). In particular, the role ofa specific perturbation prevailing in Light Water Reactors, the propagating densityperturbation, in the stability of BWRs and on the noise field of LWRs in general, isinvestigated by considering three topics. LÄS MER

  5. 9. Mesoscopic superconductivity : quasiclassical approach

    Författare :Marek Ožana; Andrei Shelankov; Dierk Rainer; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mesoscopic superconductivity; quasiclassical theory; boundary conditions; multi-layer structures; Gor kov equations; quasiclassical Green s function; Green s function on classical trajectories;

    Sammanfattning : This Thesis is concerned with the quasiclassical theory of meso-scopic superconductivity. The aim of the Thesis is to introduce the boundary conditions for a quasiclassical Green’s function on partially transparent interfaces in mesoscopic superconducting structures and to analyze the range of applicability of the quasiclassical theory. LÄS MER

  7. 10. Theoretical Developments for the Real-Time Description and Control of Nanoscale Systems

    Författare :Miroslav Hopjan; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Green’s Function; DFT; TDDFT; Hubbard Model; Many-Body Perturbation Theory; Strongly Correlated Systems; Quantum Transport; Disorder; Ehrenfest Dynamics; Electronic Friction; Exact Diagonalization; Periodic Anderson Model; Fysicumarkivet A:2018:Hopjan;

    Sammanfattning : In this thesis we focus on improvements of the description of the electron-electron correlation effects in nonequilibrium nanosystems. We mainly focus on developments of two nonequilibrium methods, namely the formalism of Nonequilibrium Green’s Function and Time Dependent Density Functional Theory and we explore the possibility to improve existing approximations in these theories. LÄS MER