Sökning: "Kondenserade materiens fysik"
Visar resultat 16 - 20 av 1052 avhandlingar innehållade orden Kondenserade materiens fysik.
16. Numerical studies of spin chains and cold atoms in optical lattices
Sammanfattning : An important, but also difficult, research field in condensed matter physics is that of strongly correlated systems. This thesis considers two topics in this field. The first topic is disorder and frustration in spin models. The introduction of disorder into quantum spin chains creates a complex problem. LÄS MER
17. Theory of Crystal Fields and Magnetism of f-electron Systems
Sammanfattning : A parameter free approach for the calculation of the crystal field splitting of the lowest Russel-Saunders J-multiplet in f-electron systems has been developed and applied to selected compounds. The developed theory is applicable to general symmetries and is based on symmetry constrained density functional theory calculations in the local density or in the generalised gradient approximation. LÄS MER
18. The influence of crystallinity on the properties of carbon nanotubes
Sammanfattning : Carbon nanotubes have been advertised as a material with quite extraordinary properties, both mechanically and electrically. The truth is that carbon nanotubes is not one material, but several different. LÄS MER
19. Strong Correlation Effects in Bosonic and Fermionic Systems Through an Unbiased Quantum Monte Carlo Approach
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
20. Development and applications of theoretical algorithms for simulations of materials at extreme conditions
Sammanfattning : Materials at extreme conditions exhibit properties that differ substantially from ambient conditions. High pressure and high temperature expose anharmonic, non-linear behavior, and can provoke phase transitions among other effects. Experimental setups to study that sort of effects are typically costly and experiments themselves are laborious. LÄS MER
