Sökning: "Spin- 1 2 chain"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden Spin- 1 2 chain.

  1. 1. Renormalization of perturbations in the spin-1/2 chain

    Författare :David Gustafsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; non-abelian bosonization; renormalization group; perturbations; operator product expansion; Spin- 1 2 chain;

    Sammanfattning : .... LÄS MER

  3. 2. Strongly Correlated Models in One Dimension from a Density Matrix Renormalization Group Perspective

    Författare :Stefan Rommer; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; matrix product states; impurities; density matrix renormalization group; Heisenberg model; spin chain; DMRG;

    Sammanfattning : The density matrix renormalization group (DMRG) is a numerical method for studying low dimensional strongly correlated models. The study of these models is one of the most active areas of condensed matter physics today and has been spurred not only by the discovery of high temperature superconductivity but also by experiments on new compounds. LÄS MER

  4. 3. Role of charge and spin fluctuations and their interplay in solids : A Green’s function approach

    Författare :Tor Sjöstrand; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Green’s function; correlations; collective excitations; screened interaction; electric polarization; orbital and spin magnetization; magnon-phonon interaction; Fierz ambiguity; time-dependent exchange-correlation potential;

    Sammanfattning : Due to the large number of electrons, solid state physics boils down to many-body approximations in which only selected types of collective excitations are taken into account, guided by the emergent properties of the material under study. In this thesis, the collective excitations of primary interest are electronic charge and spin fluctuations(plasmons and magnons) and nuclear charge fluctuations (phonons). LÄS MER

  5. 4. Strongly Interacting Electrons in One and Two Dimensions

    Författare :Fabrizio Anfuso; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : In this thesis I present a theoretical study of three differentstrongly correlated systems: Luttinger liquids, spin-1 chains andthe two-dimensional spin-1/2 Heisenberg model.For every sub-field of our research I summarize the background andprovide further details to the work presented in the appendedpapers. LÄS MER

  7. 5. Vertical charge transport in conjugated polymers

    Författare :Vasyl Skrypnychuk; Alexandr Talyzin; Ellen Moons; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; organic electronics; conjugated polymers; nanotechnology; nanoimprint lithography; graphene; P3HT; charge transport; X-ray diffraction; structure; crystallite orientation; Materials Science; materialvetenskap;

    Sammanfattning : Conjugated polymers are novel organic electronic materials highly important for organic photovoltaic applications. Charge transport is one of the key properties which defines the performance of conjugated polymers in electronic devices. LÄS MER