Sökning: "Generalized Polarization"

Visar resultat 6 - 10 av 15 avhandlingar innehållade orden Generalized Polarization.

1. 6. Bulk-boundary correspondence in non-Hermitian systems

   Författare :Elisabet Edvardsson; Emil J. Bergholtz; Vladimir Juričić; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

   Sammanfattning : The bulk-boundary correspondence, which in topological insulators describes the relationship between the bulk invariant computed for a system with periodic boundary conditions and the number of boundary states in the corresponding system with open boundary conditions, is well-known and important for predicting the behavior of these systems. In recent years, however, the modeling of dissipative and non-equilibrium systems using non-Hermitian Hamiltonians has become increasingly popular. LÄS MER

3. 7. Non-Orthogonality and Electron Correlations in Nanotransport : Spin- and Time-Dependent Currents

   Författare :Jonas Fransson; Antti-Pekka Jauho; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; non-orthogonality; non-equilibrium; transport; nanosystem; quantum dot; spin-dependent; renormalization; Green function; diagram technique; many-body states; Hubbard operator; electron correlations; time-dependent; Fysik; icke-ortogonal; icke-jämvikt; transport; nanosystem; kvantprick; spinberoende; renormering; Green-funktion; diagramteknik; mångkropparstillstånd; Hubbadoperator; elektronkorrelationer; tidsberoende; Physics; Fysik; Fysik; Physics;

   Sammanfattning : The concept of the transfer Hamiltonian formalism has been reconsidered and generalized to include the non-orthogonality between the electron states in an interacting region, e.g. quantum dot (QD), and the states in the conduction bands in the attached contacts. LÄS MER

4. 8. Quantum chemical calculations of non-linear optical absorption

   Författare :Peter Cronstrand; KTH; []
   Nyckelord :quantum chemical; non-linear optical; multi-photon absorption;

   Sammanfattning : This thesis represents a quantum chemical treatise ofvarious types of interactions between radiation and molecularsystems, with special emphasis on the nonlinear opticalprocesses of Multi-Photon Absorption and Excited StateAbsorption. Excitation energies, transition dipole moments,two-photon and three-photon tensor elements have beencalculated from different approaches; density functional theoryandab-initiotheory, employing different orders ofcorrelation treatment with the purpose to provide accuratevalues as well as evaluate the quality of the lower ordermethods. LÄS MER

5. 9. Dispersive and polarimetric properties of waves in space plasma

   Författare :Jan Bergman; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; Astronomi; Astronomy and astrophysics; Astronomi och astrofysik; Space Physics; rymdfysik;

   Sammanfattning : Various aspects regarding dispersive and polarimetric properties of waves in space plasma are discussed from a theoretical viewpoint, which is extended to include numerical as well as experimental studies. From a more technical viewpoint, two scientific instruments are described. LÄS MER

7. 10. Structural Information Content of the Optical Field

   Författare :Per Martinsson; Ari Friberg; Karl-Heinz Brenner; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photonics; Fotonik;

   Sammanfattning :  The communication modes are a mathematical technique for the description of structural information in optical fields. These modes are orthogonal, optimally  connected functions characteristic of the optical system. Mathematically they are obtained by the singular value decomposition (SVD) of the operator that represents the field propagation. LÄS MER