Sökning: "Quantum mechanical effects"

Visar resultat 11 - 15 av 58 avhandlingar innehållade orden Quantum mechanical effects.

  1. 11. A Classical-Light Attack on Energy-Time Entangled Quantum Key Distribution, and Countermeasures

    Författare :Jonathan Jogenfors; Jan-Åke Larsson; Arnt Inge Vistnes; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Quantum Key Distribution; Energy-Time Entanglement; Quantum Information; Kvantkryptering; Energi-Tid-Snärjning; Kvantinformation;

    Sammanfattning : Quantum key distribution (QKD) is an application of quantum mechanics that allowstwo parties to communicate with perfect secrecy. Traditional QKD uses polarization of individual photons, but the development of energy-time entanglement could lead to QKD protocols robust against environmental effects. LÄS MER

  2. 12. Materials for advanced energy technology from quantum-mechanical modeling

    Författare :Xiaojie Li; Levente Vitos; Tapio Rantala; KTH; []

    Sammanfattning : The present thesis addresses promising material solutions for fusion reactors from a theoretical point of view. We focus on two specific systems: W-based alloys used as plasma-facing materials and reduced activation ferritic/martensitic (RAFM, Ferich) steels used as structural materials of breeding-blanket. LÄS MER

  3. 13. Quantum mechanical models of nanomagnetism in transition metal clusters and diluted magnetic semiconductors

    Författare :Olof Strandberg; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; diluted magnetic semiconductors; Mn As; Ga; transition metal clusters; magnetic anisotropy; Nanomagnetism; quantum geometric phases; Chern numbers; effective spin Hamiltonians; dimers;

    Sammanfattning : This dissertation investigates nanomagnetism in small transition metal clusters and the diluted magnetic semiconductor (Ga,Mn)As. We derive quantum mechanical models aimed at a realistic description of the low energy physics in these systems. LÄS MER

  4. 14. Fluorescent quantum dots and graphene-based sensors for forensic applications

    Författare :Johnny Jussi; Ying Fu; Simon Dunne; Qin Wang; Ingemar Petermann; Xin Wang; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Graphene; Quantum Dots; Blood; Forensics; Drugs; Biologisk fysik; Biological Physics;

    Sammanfattning : A key emerging concept within the forensic sciences today areportable measurementdevices, where a much more efficient usage of the resources involved with crime-solving is possible if confirmatory measurements can be realised directly at a crimescene with such devices. Today, the majority of the presently used methods duringcriminal investigation at a crime scene involves measurements of a presumptivenature, which is a vital tool as it enables the screening of samples. LÄS MER

  5. 15. Light-Matter Interaction and Quantum Computing in Rare-Earth-Ion-Doped Crystals

    Författare :Adam Kinos; Atomfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Rare-Earth-Ion-Doped Crystals; Quantum Computing; Light-Matter Interaction; Fysicumarkivet A:2018:Kinos;

    Sammanfattning : In this thesis, crystals of yttrium orthosilicate (Y2SiO5) that are randomly doped with another rare-earth element, such as praseodymium (Pr), europium (Eu), or cerium (Ce), are investigated with lasers locked to ultra-stable cavities using the Pound-Drever-Hall locking technique. Many of these rare-earth elements have long-lived 4f-4f transitions, hundreds of microseconds to a few milliseconds, with even longer ground hyperfine lifetimes of up to several days. LÄS MER