Sökning: "quantum dynamics"

Visar resultat 16 - 20 av 340 avhandlingar innehållade orden quantum dynamics.

1. 16. Quantum Coherence and Quantum-Vacuum Effects in Some Artificial Electromagnetic Media

   Författare :Jianqi Shen; Sailing He; Chris Phillips; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Quantum coherence; quantum vacuum; electromagnetically induced transparency; negative refractive index; artificial electromagnetic media; electric- and magnetic-dipole transitions; multilevel atomic vapors; transient evolution; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : The author of this thesis concentrates his attention on quantum optical properties of some artificial electromagnetic media, such as quantum coherent atomic vapors (various multilevel electromagnetically induced transparency vapors) and negative refractive index materials, and suggests some possible ways to manipulate wave propagations inside the artificial electromagnetic materials based on quantum coherence and quantum vacuum effects. In Chapters 1 and 2, the author reviews the previous papers on quantum coherence as well as the relevant work such as electromagnetically induced transparency (EIT), atomic population trapping and their various applications. LÄS MER

3. 17. Reaction dynamics on highly excited states

   Författare :Johanna Brinne Roos; Åsa Larson; Ioan F. Schneider; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ab initio calculations; dissociative recombination; resonant ion-pair formation; mutual neutralization; molecular electronic states; molecule-electron collisions; quantum chemistry; molecular dynamics; Chemical physics; Kemisk fysik; Molecular physics; Molekylfysik; kemisk fysik; Chemical Physics;

   Sammanfattning : In this thesis I have performed theoretical studies on the reaction dynamics in few-atom molecules. In particular, I have looked at reaction processes in which highly excited resonant states are involved. LÄS MER

4. 18. Measuring quantum systems with a tunnel junction

   Författare :Joachim Wabnig; Jörgen Rammer; Ulrich Eckern; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum mechanics; quantum measurement; tunnel junction; qubit; nanomechanics; noise; Physics; Fysik;

   Sammanfattning : This thesis is concerned with employing the statistics of charge transfer in a conductor as a tool for quantum measurement. The physical systems studied are electronic devices made by nanoscale manufacturing techniques. In this context quantum measurement appears not as a postulate, but as physical process. LÄS MER

5. 19. Quantum dynamical effects in complex chemical systems

   Författare :S. Karl-Mikael Svensson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Quantum dynamics; Radiative association; Classical Wigner method; Feynman path integral; Reaction rate constants; Wigner phase space;

   Sammanfattning : When using mathematical models to computationally investigate a chemical system it is important that the methods used are accurate enough to account for the relevant properties of the system and at the same time simple enough to be computationally affordable. This thesis presents research that so far has resulted in three published papers and one unpublished manuscript. LÄS MER

7. 20. Quantum electronic transport in low-dimensional semiconductors

   Författare :Heiner Linke; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum transport; two-dimensional electron gas; contact-free characterisation; ballistic transport; mesoscopic; electron billiard; quantum dot; electron-electron interaction; non-linear; phase breaking; Halvledarfysik; Fysicumarkivet A:1997:Linke; non-symmetric conductio; Semiconductory physics; low-dimensional structures;

   Sammanfattning : Electronic transport is studied at low temperatures in two-dimensional electron gases (2DEGs) and in mesoscopic semiconductor microstructures. The method of microwave-detection of the Shubnikov-de Haas effect for the contact-free characterisation of transport properties of 2DEGs is explored using both magnetic-field modulation and light-induced carrier modulation. LÄS MER