The low–energy excited states of a system of interacting one–dimensional fermions in a conducting state are collective charge and spin density oscillations. The unusual physical properties of such a system (called “Luttinger liquid”) are characterized by the velocities uρ and uσ of the charge and spin excitations, as well as by a parameter Kρ that determines the power law behavior of correlatio...

The spin1 2 Falicov-Kimball model is solved exactly on an infinite-coordination-number Bethe lattice in the thermodynamic limit. This model is a paradigm for a charge-transfer metal-insulator transition, where the occupancy of localized and delocalized electronic orbitals rapidly changes at the metal-insulator transition ~rather than the character of the electronic states changing from insulati...

The 4-intersection, a model for the representation of topological relations between 2-dimensional objects with connected boundaries and connected interiors, is extended to cover topological relations between 2-dimensional objects with arbitrary holes, called regions with holes. Each region with holes is represented by its generalized region—the union of the object and its holes— and the closure...

Correlations of the topological charge Q, the electric current J and the magnetic current J in SU(2) lattice gauge theory in the Maximal Abelian projection are investigated. It occurs that the correlator ≪ QJJ ≫ is nonzero for a wide range of values of the bare charge. It is shown that: (i) the abelian monopoles in the Maximal Abelian projection are dyons which carry fluctuating electric charge...

Andreas Schäfer Universität Regensburg, Institut für Physik, 93040 Regensburg, Germany E-mail: [email protected] We systematically compare three filtering methods used to extract topological excitations from lattice gauge configurations, namely smearing, Laplace filtering and the filtered fermionic topological charge (with chirally improved fermions). Each of these techn...

The surface states in three-dimensional (3D) topological insulators can be described by a twodimensional (2D) continuous Dirac Hamiltonian. However, there exists the Fermion doubling problem when putting the continuous 2D Dirac equation into a lattice model. In this paper, we introduce a Wilson term with a zero bare mass into the 2D lattice model to overcome the difficulty. By comparing with a ...

We initiate a study of topological orthoalgebras (TOAs), concentrating on the compact case. Examples of TOAs include topological orthomodular lattices, and also the projection lattice of a Hilbert space. As the latter example illustrates, a lattice-ordered TOA need not be a topological lattice. However, we show that a compact Boolean TOA is a topological Boolean algebra. Using this, we prove th...