English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We study the single channel (compactified) models, the sigma-tau model andthe O(3) symmetric Anderson model, which were introduced by Coleman et al., andColeman and Schofield, as a simplified way to understand the low energybehaviour of the isotropic and anisotropic two channel Kondo systems. Thesemodels display both Fermi liquid and marginal Fermi liquid behaviour and anunderstanding of the nature of their low energy fixed points may give somegeneral insights into the low energy behaviour of other strongly correlatedsystems. We calculate the excitation spectrum at the non-Fermi liquid fixedpoint of the sigma-tau model using conformal field theory, and show that theresults are in agreement with those obtained in recent numericalrenormalization group (NRG) calculations. For the O(3) Anderson model we findfurther logarithmic corrections in the weak coupling perturbation expansion tothose obtained in earlier calculations, such that the renormalized interactionterm now becomes marginally stable rather than marginally unstable. We derive aWard identity and a renormalized form of the perturbation theory thatencompasses both the weak and strong coupling regimes and show that thechi/gamma ratio is 8/3 (chi is the total susceptibility, spin plus isospin),independent of the interaction U and in agreement with the NRG calculations.Comment: 23 pages, LaTeX, 11 figures includes as eps-files, submitted to Phys.  Rev.

Low-energy fixed points of the σ-τ and the O(3) symmetric Anderson models