Sökning: "hubbard"
Visar resultat 21 - 25 av 50 avhandlingar innehållade ordet hubbard.
21. Non-Linear Canonical Methods in Strongly Correlated Electron Systems
Sammanfattning : In this thesis some new ideas to perform the analysis of Strongly Correlated Electronic Systems (SCES) are developed. In particular the use of non-linear canonical transformations is considered thoroughly. LÄS MER
22. Role of charge and spin fluctuations and their interplay in solids : A Green’s function approach
Sammanfattning : Due to the large number of electrons, solid state physics boils down to many-body approximations in which only selected types of collective excitations are taken into account, guided by the emergent properties of the material under study. In this thesis, the collective excitations of primary interest are electronic charge and spin fluctuations(plasmons and magnons) and nuclear charge fluctuations (phonons). LÄS MER
23. Correlated Electronic Structure of Materials : Development and Application of Dynamical Mean Field Theory
Sammanfattning : This thesis is dedicated to the development, implementation and application of a combination of Density Functional Theory and Dynamical Mean Field Theory. The resulting program is shown through several examples to be a powerful and flexible tool for calculating the electronic structure of strongly correlated materials. LÄS MER
24. Many-photon effects in time-resolved second harmonic generation from systems in optical cavities
Sammanfattning : 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. LÄS MER
25. Nanospintronics with Molecular Magnets - Tunneling and Spin-Electric Coupling
Sammanfattning : This dissertation investigates theoretically electric control of the magnetic properties of molecular magnets. Two classes of magnetic molecules are considered. The first class consists of molecules that are spin frustrated. LÄS MER