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Hittade 2 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Ab initio Lattice Dynamics : Hydrogen-dense and Other Materials

   Författare :Duck Young Kim; Rajeev Ahuja; Richard Needs; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Density functional theory; Density functional perturbation theory; Hydrogen-dense materials; Phase transition; High pressure; Ab initio lattice dynamics; Superconductivity; Quasi-particle approximation; Physics; Fysik;

   Sammanfattning : This thesis presents a theoretical study of materials under high pressure using ab initio lattice dynamics based on density functional theory and density functional perturbation theory using both super-cell and linear response approach. Ab initio lattice dynamics using super-cell approach is applied to compare our theoretical predictions with experimental findings. LÄS MER

3. 2. Model Vertices Beyond the GW Approximation

   Författare :Mikael Hindgren; Matematisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matematisk och allmän teoretisk fysik; thermodynamics; statistical physics; gravitation; GW approximation; Electron self energy; Green s function; consistency; local-field corrections; vertex function; conserving approximations; variational energies; Mathematical and general theoretical physics; classical mechanics; relativity; quantum mechanics; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Fysicumarkivet A:1997:Hindgren;

   Sammanfattning : We study the effects of local vertex corrections to the self energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self energies without including the explicit time dependence of the exchange-correlation potential provided, however, that a proper decay at large momentum transfer (large q) is built into the vertex function. LÄS MER