Sökning: "Quasiparticle."

Visar resultat 1 - 5 av 40 avhandlingar innehållade ordet Quasiparticle..

1. 1. Self-consistency and the GW-approximation

   Författare :Bengt Holm; Matematisk fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matematisk och allmän teoretisk fysik; thermodynamics; Spectral Function; Greens functions; Self-energy; classical mechanics; Mathematical and general theoretical physics; Quasiparticle.; quantum mechanics; relativity; statistical physics; gravitation; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Fysicumarkivet A:1997:Holm;

   Sammanfattning : The effects of self-consistency in the GW-approximation are studied. The $GWA$ is known to describe the electronic properties of a wide range of materials very well. However, the calculations made so far have not taken into account the issue of self-consistency, which is implied in the original formulation of the $GWA$. LÄS MER

3. 2. Design Of Dual Polarisation Sideband Separation Mixer For ALMA Band 5

   Författare :Bhushan Billade; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Millimeter wave receivers; Millimeter wave mixers; Superconductor-Insulator-Superconductor mixers; Thin film circuits.; Quasiparticle mixers;

   Sammanfattning : This licentiate is focused on the design and development of Superconductor-Insulator-Superconductor (SIS) junction mixer for ALMA Band 5, one of the ten frequency bands of the Atacama Large Millimeter Array (ALMA) project. ALMA Band 5 is a dual polarisation sideband separation heterodyne receiver covering radio frequencies (RF) from 163 GHz to 211 GHz, with 4-8 GHz intermediate frequency (IF). LÄS MER

4. 3. Planar Quasiparticle Mixer Structures for Millimeter and Sub-Millimeter Wave Receivers

   Författare :Anders Skalare; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; SIS receiver; dipole array antenna; slot substrate mode loss; millimeter wave regime; planar antennas; sub-millimeter wave regime; superconducting mixers; slot radiation; slot lines; slot wavelengths; Voltage Matching Method;

   Sammanfattning : The paper covers various aspects of integrating planar antennas with superconducting mixers in the millimeter and sub-millimeter wave regime. The construction of an 80-100 GHz tapered slot antenna and SIS mixer chip with a minimum double side band noise temperature of 240 K is described. LÄS MER

5. 4. Many-body Problems in the Theory of Stellar Collapse and Neutron Stars

   Författare :Emma Olsson; Bengt Gustafsson; Christopher Pethick; Bengt Friman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; neutron stars; core-collapse supernovae; response functions; Fermi liquids; nuclear matter; neutrino interactions; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik;

   Sammanfattning : When modelling the collapse of massive stars leading to supernova explosions and the cooling of neutron stars, understanding the microphysical processes, such as the interaction of neutrinos within a dense medium are of vital importance. The interaction of neutrinos with nucleons (neutrons and protons) is altered by the presence of the medium, compared to the same process with free nucleons. LÄS MER

7. 5. Symmetry, Disorder and the Josephson Effect in d-Wave Superconductors

   Författare :Fabian Wenger; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; density of states; Josephson effect; high-Tc; symmetry; cuprate; disorder; d-wave; superconductor; order parameter;

   Sammanfattning : This thesis focuses on aspects of symmetry, disorder and the Josephson effect in d-wave superconductors which are generically characterized by sign changes of the gap function .DELTA.k in certain directions with respect to the underlying crystal lattice. LÄS MER