Per Fröjdh

Kondo effect in a Luttinger liquid: Exact results from conformal field theory.

We report on exact results for the low-temperature thermodynamics of a spin-

FRUSTRATED HONEYCOMB HEISENBERG ANTIFERROMAGNET : A SCHWINGER-BOSON APPROACH

frac{1}{2}

Magnetic impurity in a Luttinger liquid: A conformal field theory approach.

magnetic impurity coupled to a one-dimensional interacting electron system. By using boundary conformal field theory, we show that there are only two types of critical behaviors consistent with the symmetries of the problem: {em either} a local Fermi liquid, {em or} a theory with an anomalous response identical to that recently proposed by Furusaki and Nagaosa. Suppression of back scattering off the impurity leads to the same critical properties as for the two-channel Kondo effect.

Interacting electrons and localized spins: Exact results from conformal field theory

We analyze the frustrated Heisenberg antiferromagnet defined on a honeycomb lattice using a Schwinger-boson mean-field theory. The spin-wave velocity and the susceptibility are presented as functions of the strength of the frustrating interaction for spin S=1/2, and the dynamic structure factor is calculated for various temperatures and frustrations. For large S, we find an increased Neel stability with respect to the classical case.

Magnetic impurity in a Luttinger liquid: a view from conformal field theory

We study the low-temperature properties of a spin-onehalf magnetic impurity coupled to a one-dimensional interacting electron system. Using the newly developed formalism by Affleck and Ludwig, with a scale invariant boundary condition replacing the impurity, we exploit boundary conformal field theory to deduce the impurity thermal and magnetic response. In the case of only forward electron scattering off the impurity, we predict the same critical scaling as for the two-channel Kondo effect for non-interacting electrons, but with a novel Wilson ratio. Backward electron scattering off the impurity destabilizes this behavior and drives the system to a new fixed point. In the case of equal amplitudes for forward- and backward scattering {em (Kondo interaction)}, we show that there are only two types of scaling behaviors consistent with the symmetries of the problem: {em either} a local Fermi liquid {em or} a critical theory with an anomalous specific heat. The latter case agrees with a recent ``poor-man-scaling result proposed by Furusaki and Nagaosa.

Run-length coding of non-coded macroblocks

We give a brief review of the Kondo effect in a one-dimensional interacting electron system, and present exact results for the impurity thermodynamic response based on conformal field theory.

Method and arrangement for adaptation in http streaming

Exact results are reported for the low-temperature thermodynamics of a spin-1/2 magnetic impurity coupled to a 1D interacting electron system. The use of conformal field theory techniques reveals that there are only two types of critical behaviors consistent with the symmetries of the problem: either a local Fermi liquid, or else a theory identical to that recently proposed by Furusaki and Nagaosa. We also show that forward electron scattering on the impurity produces the same critical behavior as the two-channel Kondo effect for noninteracting electrons.