Sökning: "quantum vacuum"

Visar resultat 11 - 15 av 49 avhandlingar innehållade orden quantum vacuum.

1. 11. Probing quantum and classical noise in nano circuits

   Författare :Arsalan Pourkabirian; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; transmon; vacuum fluctuations; circuit-QED; SET; dynamical Casimir effect; two-level fluctuator; artificial atom; SQUID; charge noise;

   Sammanfattning : This thesis presents measurements of classical and quantum noise in nano circuits.The first part of the thesis, covers extensive measurements on charge noise sources.Low-frequency charge noise with the power spectrum close to 1/f(wherefis thefrequency) has been observed in a variety of systems. LÄS MER

3. 12. Modelling and analyzing strong-field effects in quantum plasma

   Författare :Haidar Al-Naseri; Gert Brodin; Jens Zamanian; J. Tito Mendonca; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Strong-field physics; Kinetic theory; Quantum plasma; fysik; Physics;

   Sammanfattning : Under the extreme conditions that can be found around dense stars and in the accretion discs of black holes, several strong-field quantum phenomena dominate the dynamics of the plasma. This includes the creation of matter and anti-matter from the vacuum (Schwinger mechanism), radiation reaction and Landau quantization. LÄS MER

4. 13. Meson Decay with Isospin Breaking At Two Loops

   Författare :Karim Ghorbani; Teoretisk partikelfysik - Geonomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; kvantfältteori; Elementarpartikelfysik; quantum field theory; Elementary particle physics; Naturvetenskap; Natural science; hadron physics; standard model; chiral Lagrangian; quantum correction;

   Sammanfattning : In all calculations done in this thesis, the evaluation of higher order quantum corrections has been central. In the first paper included in this thesis we have investigated the effects of finite volume meson propagators for quark-antiquark vacuum expectation value at two-loop level. LÄS MER

5. 14. Theoretical studies of porphyrin proteins

   Författare :Emma Sigfridsson; Beräkningskemi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; molecular mechanics; quantum chemical calculations; electrostatic potential charges; atomic charges; ferrochelatase; cytochrome; myoglobin; Porphyrin; haem; QM MM; reorganisation energy; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi;

   Sammanfattning : Different aspects of porphyrin proteins have been studied with theoretical methods. For example, we have studied: - The importance of hydrogen bonds for the discrimination between carbon monoxide and molecular oxygen by myoglobin, the oxygen carrier in muscles, modelling the active site both in vacuum and in the protein matrix - The inner-sphere reorganisation energy during electron transfer for cytochromes compared to other electron-transfer proteins, such as blue copper proteins and Fe-S clusters - The role of porphyrin distortions in the reaction mechanism of ferrochelatase, the enzyme that inserts an iron ion into protoporphyrin IX to make haem - The interaction between different metal sites in ferrochelatase In these studies we have used density functional theory, classical force field methods, and a combination of quantum chemistry and molecular mechanics. LÄS MER

7. 15. Fast-tunable resonators and quantum electrical circuits

   Författare :Martin Sandberg; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; SEB; tunable; Sisyphus resistance; CPW; Resonator; SCB; qubit; circuit-QED; transmon; SQUID;

   Sammanfattning : In this thesis, measurements on superconducting electrical circuits that exhibit quantum mechanical effects are presented. Nonlinear superconducting circuits can be regarded as artificial atoms with energy spectra that can be engineered. The artificial atoms can be used as quantum bits for quantum computation. LÄS MER