Search for dissertations about: "collective excitations"

Showing result 1 - 5 of 38 swedish dissertations containing the words collective excitations.

2. 1. Studies of collective excitations in rare earth nuclei

   Author : Anders Axelsson; Uppsala universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiation sciences; Strålningsvetenskap; Radiation biology; Strålningsbiologi; kärnfysik; Nuclear Physics;

   Abstract : .... READ MORE

4. 2. Theoretical studies of collective electronic excitations in low-dimensional structures

   Author : Zhe Yuan; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; linear atomic chains; hydrogen storage; nanodisks; dielectric response; surface plasmon resonances; electron gas model; electronic excitation; metallic thin films; time-dependent density functional theory;

   Abstract : During the past decade, nanoplasmonics and nanophotonicshas emerged as a new branch of nanosciences with many novelapplications. Central in this development is the localized surface plasmon resonance (LSPR) tunable by the sizes and shapes at nanometer scale. READ MORE

5. 3. Role of charge and spin fluctuations and their interplay in solids : A Green’s function approach

   Author : Tor Sjöstrand; Matematisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Green’s function; correlations; collective excitations; screened interaction; electric polarization; orbital and spin magnetization; magnon-phonon interaction; Fierz ambiguity; time-dependent exchange-correlation potential;

   Abstract : 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). READ MORE

6. 4. Lateral Superlattices in Commensurate Magnetic Fields: Electronic Structure, Transport and Optical Properties

   Author : Egidijus Anisimovas; Matematisk fysik; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; tunneling; Physics; collective excitations; optical absorption; quantum Hall effect; electronic structure; two-dimensional electron systems; lateral superlattices; Electromagnetism; Fysik; optics; acoustics; Elektromagnetism; optik; akustik; Fysicumarkivet A:2001:Anisimovas;

   Abstract : The present thesis is devoted to the theoretical study of two-dimensional electron systems moving in a modulated lateral periodic potential and a competing perpendicular magnetic field. The three introductory chapters offer a brief exposition of the basic issues in this area -- the description of the electron motion in a prependicular magnetic field, the group of magnetic translations and the commensurability phenomena -- at an elementary level. READ MORE

7. 5. Photoemission from Alkali Metal Overlayers: Quantum Wells, Photoelectron Interference and Atomic Structure Changes

   Author : Dan Claesson; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; quantum well states; surface structure; alkali metals; angle resolved photoemission; surface electronic phenomena; thin films; collective excitations; electronic structure;

   Abstract : Angle resolved photoelectron spectroscopy is used to investigate alkali metal overlayers on noble metal surfaces. The work deals with interference in photoemission, bulk electronic structure and adsorption induced changes of atomic structure, respectively. The relative importance of surface and bulk in photoemission has remained largely unexplored. READ MORE