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Showing result 1 - 5 of 13 swedish dissertations matching the above criteria.

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

   Author : Miroslav Hopjan; Matematisk fysik; []
   Keywords : 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

4. 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

5. 3. Correlated materials : models and methods

   Author : Hugo Strand; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; 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

6. 4. Many-photon effects in time-resolved second harmonic generation from systems in optical cavities

   Author : Megha Gopalakrishna; Matematisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Second harmonic generation; Cavity optics; Non-linear optics; Cavity leakage; Ultracold atoms; Dicke model; Exact diagonalization; Non-equilibrium Green s functions; Fysicumarkivet A:2024:Gopalakrishna;

   Abstract : Second harmonic generation is popular due to its numerous applications in different technologies dealing with multiple fields of science. The rapid technical advancement with the second harmonic generation demands parallel development in the theoretical understanding. READ MORE

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

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

   Abstract : .... READ MORE