Sökning: "density matrix renormalization group"

Visar resultat 6 - 8 av 8 avhandlingar innehållade orden density matrix renormalization group.

  1. 6. Study of the phase diagram of Zn symmetric chains

    Författare :Iman Mahyaeh; Eddy Ardonne; Supriya Krishnamurthy; Joost Slingerland; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

    Sammanfattning : In this thesis we study the phase diagrams of Zn symmetric chains. We start with investigating the topological phases of the Kitaev chain, a Z2 symmetric model, with long range couplings and a phase gradient. LÄS MER

  3. 7. Numerical studies of spin chains and cold atoms in optical lattices

    Författare :Sara Bergkvist Sylvan; Anders Rosengren; Richard Scalettar; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Teoretisk Fysik; Kondenserade materiens teori; Condensed matter physics; Kondenserade materiens fysik;

    Sammanfattning : An important, but also difficult, research field in condensed matter physics is that of strongly correlated systems. This thesis considers two topics in this field. The first topic is disorder and frustration in spin models. The introduction of disorder into quantum spin chains creates a complex problem. LÄS MER

  4. 8. 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