Search for dissertations about: "Exact Diagonalization"

Showing result 1 - 5 of 12 swedish dissertations containing the words Exact Diagonalization.

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

    Author : Miroslav Hopjan; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; 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;

    Abstract : 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. READ MORE

  2. 2. Gaps, Traps and Lattices - Correlations in Small Quantum Systems

    Author : Magnus Borgh; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetiska och optiska ; egenskaper elektriska; Cold atoms; Quantum dots; Optical lattices; classical mechanics; Mathematical and general theoretical physics; Exact diagonalization; Density Functional Theory; Vortices; relativity; quantum mechanics; termodynamik; statistisk fysik; relativitet; kvantmekanik; klassisk mekanik; Matematisk och allmän teoretisk fysik; thermodynamics; statistical physics; Condensed matter:electronic structure; gravitation; supraledare; magnetisk resonans; electrical; magnetic and optical properties; supraconductors; magnetic resonance; relaxation; spectroscopy; Kondenserade materiens egenskaper:elektronstruktur; spektroskopi; Fysicumarkivet A:2007:Borgh;

    Abstract : This dissertation investigates properties of two-dimensional many-body systems. Studies are performed using the Spin-Density Functional Theory with the Local Spin-Density Approximation, and numerical exact diagonalization. READ MORE

  3. 3. Correlated materials : models and methods

    Author : Hugo Strand; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; correlated electrons; Hubbard model; multiband Hubbard model; dynamical mean field theory; exact diagonalization; Landau theory; Mott metal-insulator transition; Gutzwiller method; many-body point group symmetry; ironchalcogenides; Kanamori interaction; Slater-Condon interaction;

    Abstract : This thesis encompass a series of studies on methods and models for electron systems with local interactions, relevant for correlated materials. The first study focus on the canonical model for local correlation, the Hubbard model. READ MORE

  4. 4. Few- to many-body physics in ultracold gases : An exact diagonalization approach

    Author : Johannes Bjerlin; NanoLund: Center for Nanoscience; []
    Keywords : ;

    Abstract : .... READ MORE

  5. 5. Vortices and Persistent Currents in Rotating Bose Gases - a Diagonalization Approach

    Author : Sara Bargi; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Bose-Einstein condensation; vortices; superfluidity; Fysicumarkivet A:2010:Bargi;

    Abstract : In this thesis, I explore the behavior of rotating ultra-cold Bose gases, by diagonalizing the Hamiltonian. This method has the advantage of being exact in the limit of weak interactions, and thus is a useful complement to the more commonly used Gross-Pitaevskii (GP) equation, which relies on a mean-field approximation. READ MORE