Sökning: "Heisenberg group"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden Heisenberg group.

  1. 1. 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

  3. 2. Anyons and antiferromagnets : two two-dimensional topics

    Författare :Torbjörn Einarsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; antiferromagnet; two dimension; anyons; fractional statistics; Heisenberg model; torus; nonlinear sigma model; multi-component wavefuntions; spin; Néel phase; disorder; braid group;

    Sammanfattning : .... LÄS MER

  4. 3. Spectral estimates for the magnetic Schrödinger operator and the Heisenberg Laplacian

    Författare :Anders Hansson; Ari Laptev; B Malcolm Brown; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectral theory; Schrödinger operator; magnetic field; Aharonov-Bohm; Lieb-Thirring; diamagnetic inequality; Heisenberg group; Heisenberg Laplacian; hypoelliptic; spektralteori; Schrödingeroperator; magnetfält; Aharonov-Bohm; Lieb-Thirring; diamagnetisk olikhet; Heisenberggrupp; Heisenberg-Laplace-operator; hypoelliptisk; MATHEMATICS; MATEMATIK;

    Sammanfattning : I denna avhandling, som omfattar fyra forskningsartiklar, betraktas två operatorer inom den matematiska fysiken. De båda tidigare artiklarna innehåller resultat för Schrödingeroperatorn med Aharonov-Bohm-magnetfält. LÄS MER

  5. 4. Quasi-Lie Algebras and Quasi-Deformations. Algebraic Structures Associated with Twisted Derivations

    Författare :Daniel Larsson; Matematik LTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Talteori; fältteori; algebraisk geometri; algebra; gruppteori; Lie Algebras; Quasi-Deformations; Number Theory; field theory; algebraic geometry; group theory; Quasi-Lie Algebras;

    Sammanfattning : This thesis introduces a new deformation scheme for Lie algebras, which we refer to as ?quasi-deformations? to clearly distinguish it from the classical Grothendieck-Schlessinger and Gers-tenhaber deformation schemes. The main difference is that quasi-deformations are not in gene-ral category-preserving, i.e. LÄS MER

  7. 5. Critical point theory with applications to semilinear problems without compactness

    Författare :Sara Maad; Jacqueline Fleckinger; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; MATEMATIK; MATHEMATICS; MATEMATIK; Mathematics; Matematik;

    Sammanfattning : The thesis consists of four papers which all regard the study of critical point theory and its applications to boundary value problems of semilinear elliptic equations. More specifically, let Ω be a domain, and consider a boundary value problem of the form -L u + u = f(x,u) in Ω, and with the boundary condition u=0. LÄS MER