Sökning: "hubbard"

Visar resultat 16 - 20 av 50 avhandlingar innehållade ordet hubbard.

  1. 16. Strong Correlation Effects in Bosonic and Fermionic Systems Through an Unbiased Quantum Monte Carlo Approach

    Författare :Emil Blomquist; Egor Babaev; Johan Carlström; Barbara Capogrosso Sansone; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fysik; Physics; Teoretisk fysik; Theoretical Physics;

    Sammanfattning : Strongly interacting many-body quantum systems constitute some of the most challenging problems in physics, and exact analytical solutions are rare. In this thesis, we will investigate the models of two such systems numerically using the unbiased worm-algorithm Monte Carlo method. LÄS MER

  3. 17. Spin splitting in open quantum dots and related systems

    Författare :Martin Evaldsson; Igor Zozoulenko; Igor Abrikosov; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mesoscopic systems; 2DEG; ballistic transport; quantum dots; spin-polarised transport in quantum dots; spontanueous spin-splitting; Mesoscopic physics; Mesoskopisk fysik;

    Sammanfattning : This thesis addresses electron spin phenomena in semi-conductor quantum dots/anti-dots from a computational perspective. In the first paper (paper I) we have studied spin-dependent transport through open quantum dots, i.e., dots strongly coupled to their leads, within the Hubbard model. LÄS MER

  4. 18. Finite Energy Electronic Correlationsin Low-Dimensional Systems

    Författare :Daniel Bozi; Portugal Universidade do Minho; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis report deals with the 1D Hubbard model and the quantum objects that diagonalize the normal ordered Hubbard hamiltonian, among those the so called PseudoFermions (PFs). These PFs have no residual energy interactions, are eta-spin and spin zero objects, and are the scatterers and the scattering centers of the theory. LÄS MER

  5. 19. Physics of Strong Correlations in Electronic Structure and Model Calculations

    Författare :Urban Lundin; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Strongly correlated electrons; Electronic structure calculations; Fysik; Physics; Fysik; fysik; Physics;

    Sammanfattning : Using field theoretical methods models of strongly correlated electrons have been investigated. Application to electronic structure calculations has been made. LÄS MER

  7. 20. Transport phenomena in quantum wells and wires in presence of disorder and interactions

    Författare :Valeria Vettchinkina; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; time-dependent density-functional theory; disorder; electron correlation; Lowdimensional semiconducting systems; transport phenomena; Fysicumarkivet F:2012:Vettchinkina;

    Sammanfattning : Present-day electronics employ circuits of smaller and smaller dimensions, and today the length scales are so small that the laws of physics which rule micro-cosmos, quantum mechanics, become directly important. This thesis reports on theoretical work on electron transport in different nanostructures. LÄS MER