Irrational Versus Rational Charge and Statistics in Two-Dimensional Quantum Systems

Rational and Irrational Bubbles

Spin-charge separation in two-dimensional frustrated quantum magnets.

The dynamics of a mobile hole in two-dimensional frustrated quantum magnets is investigated by exact diagonalization techniques. Our results provide evidence for spin-charge separation upon doping the kagome lattice, a prototype of a spin liquid. In contrast, in the checkerboard lattice, a symmetry broken valence bond crystal, a small quasiparticle peak is seen for some crystal momenta, a findi...

Braid group statistics in two-dimensional quantum field theory

Within the framework of algebraic quantum field theory, we construct explicitly localized morphisms of a Haag-Kastler net in 1 + 1dimensional Minkowski space showing abelian braid group statistics. Moreover, we investigate the scattering theory of the corresponding quantum fields.

Spin-charge decoupling and orthofermi quantum statistics

Currently Gutzwiller projection technique and nested Bethe ansatz are two main methods used to handle electronic systems in the U infinity limit. We demonstrate that these two approaches describe two distinct physical systems. In the nested Bethe ansatz solutions, there is a decoupling between the spin and charge degrees of freedom. Such a decoupling is absent in the Gutzwiller projection techn...

Two-dimensional Proper Rational Matrices and Causal Input/output Representations of Two-dimensional Behavioral Systems∗

The concept of proper rational matrix is strictly connected with the representation of causal transfer matrices. In the two-dimensional (2D) case there is much freedom in defining proper rational matrices. This freedom is connected to the fact that past and future in the 2D case can be determined by a 2D cone. In this way the concept of rational matrix which is proper with respect to a cone can...