Sökning: "NATURAL SCIENCES Physics Other physics Mathematical physics"

Visar resultat 16 - 20 av 177 avhandlingar innehållade orden NATURAL SCIENCES Physics Other physics Mathematical physics.

  1. 16. Some Aspects of Chirality: fermion masses and chiral p-forms

    Detta är en avhandling från Department of Mathematical Physics, Lund University

    Författare :Astri Kleppe; Lunds universitet.; Lund University.; [1997]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; relativitet; kvantmekanik; klassisk mekanik; Matematisk och allmän teoretisk fysik; massive neutrinos; fermion masses; Mathematical and general theoretical physics; self-dual fields; democratic family mixing; quantum mechanics; classical mechanics; relativity; gravitation; thermodynamics; statistical physics; statistisk fysik; termodynamik; Elementary particle physics; quantum field theory; Elementarpartikelfysik; kvantfältteori; Fysicumarkivet A:1997:Kleppe;

    Sammanfattning : Popular Abstract in Swedish Denna avhandling handlar till stor del om elementarpartiklars massor. I motsats till många av de andra av elementarpartiklarnas egenskaper, uppvisar partiklarnas massor inget iögonfallande mönster. De antar dessutom värden som spänner över ett mycket stort område. LÄS MER

  2. 17. First principles methods for electronic structure calculations of solids

    Detta är en avhandling från Department of Theoretical Physics, Lund University

    Författare :Martin Springer; Lunds universitet.; Lund University.; [1997]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; screened interaction; T-matrix; vertex function; GW approximation; Green function; density functional theory; gradient expansion; order N method; Physics; Fysik;

    Sammanfattning : A straightforward gradient expansion of the exchange energy of a perturbed electron gas is performed. Studied perturbations range from very weak to those that produce, e.g., a silicon-like band structure with a band gap. LÄS MER

  3. 18. Lateral Superlattices in Commensurate Magnetic Fields: Electronic Structure, Transport and Optical Properties

    Detta är en avhandling från Division of Solid State Theory, Lund University, Sölvegatan 14A, S-223 62 Lund, SWEDEN

    Författare :Egidijus Anisimovas; Lunds universitet.; Lund University.; [2001]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tunneling; Physics; collective excitations; optical absorption; quantum Hall effect; electronic structure; two-dimensional electron systems; lateral superlattices; Electromagnetism; Fysik; optics; acoustics; Elektromagnetism; optik; akustik; Fysicumarkivet A:2001:Anisimovas;

    Sammanfattning : The present thesis is devoted to the theoretical study of two-dimensional electron systems moving in a modulated lateral periodic potential and a competing perpendicular magnetic field. The three introductory chapters offer a brief exposition of the basic issues in this area -- the description of the electron motion in a prependicular magnetic field, the group of magnetic translations and the commensurability phenomena -- at an elementary level. LÄS MER

  4. 19. Quantum scattering and interaction in graphene structures

    Detta är en avhandling från Linköping : Linköping University Electronic Press

    Författare :Anna Orlof; Linköpings universitet.; Linköpings universitet.; [2017]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Since its isolation in 2004, that resulted in the Nobel Prize award in 2010, graphene has been the object of an intense interest, due to its novel physics and possible applications in electronic devices. Graphene has many properties that differ it from usual semiconductors, for example its low-energy electrons behave like massless particles. LÄS MER

  5. 20. Model Vertices Beyond the GW Approximation

    Detta är en avhandling från Department of Theoretical Physics, Lund University

    Författare :Mikael Hindgren; Lunds universitet.; Lund University.; [1997]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matematisk och allmän teoretisk fysik; thermodynamics; statistical physics; gravitation; GW approximation; Electron self energy; Green s function; consistency; local-field corrections; vertex function; conserving approximations; variational energies; Mathematical and general theoretical physics; classical mechanics; relativity; quantum mechanics; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Fysicumarkivet A:1997:Hindgren;

    Sammanfattning : We study the effects of local vertex corrections to the self energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self energies without including the explicit time dependence of the exchange-correlation potential provided, however, that a proper decay at large momentum transfer (large q) is built into the vertex function. LÄS MER