Solution of the Multichannel Kondo Problem

We construct and solve numerically the thermodynamic Bethe Ansatz equations for the spinanisotropic two-channel Kondo model in arbitrary external field h. At high temperatures the specific heat and the susceptibility show power law dependence. For h → 0 and at temperatures below the Kondo temperature TK a two-channel Kondo effect develops characterized by a Wilson ratio 8/3, and a logarithmic divergence of the susceptibility and the linear specific heat coefficient. Finite magnetic field, h > 0 drives the system to a Fermi liquid fixed point with an unusual Wilson ratio which depends sensitively on h.

show abstract

“…(A13), this yields Eq. (17). As a further test, one can compare this result with the exact relation, Eq.…”

Section: Discussionmentioning

confidence: 99%

“…[ 17] to eliminate the flavor degrees of freedom. The fused equations considerably simplify with the choice c ≡ µ ϑ .…”

Section: Bethe-ansatz Solutionmentioning

confidence: 99%

Thermodynamics of the anisotropic two-channel Kondo problem

et al. 2002

View full text Add to dashboard Cite

show abstract

“…The comparison of the CTMA result with exact methods like NRG 18 or BA 7,8,44 can be made quantitative.…”

Section: Spin Susceptibilitymentioning

confidence: 99%

Dynamical properties of the Anderson impurity model within a diagrammatic pseudoparticle approach

2004

View full text Add to dashboard Cite

The Anderson model of a twofold spin degenerate impurity level in the limit of infinite Coulomb repulsion, U → ∞, coupled to one and two degenerate conduction bands or channels, is considered in pseudo-particle representation. We extend the Conserving T-Matrix Approximation (CTMA), a general diagrammatic approximation scheme based on a fully renormalized computation of twoparticle vertex functions in the spin and in the charge channel, to the calculation of thermodynamic and spectral properties. In the single-channel case, the CTMA yields in the Kondo regime a temperature independent Pauli spin susceptibility for temperatures below the Kondo temperature TK and down to the lowest temperatures considered, reproducing the exact spin screening in the Fermi liquid state. The impurity spectral density appears to remain non-singular down to the lowest temperatures, in agreement with Fermi liquid behavior. However, the unitarity sum rule, which is crucial for an impurity solver like the CTMA to be applicable within Dynamical Mean Field Theories for strongly correlated lattice models, is overestimated at the lowest temperatures. We argue that this shortcoming may be due to numerical imprecision and discuss an appropriate scheme for its correction. In the two-channel case, the spectral density calculated within CTMA exhibits qualitatively the correct non-Fermi liquid behavior at low temperatures, i.e. a powerlaw singularity.

show abstract

“…The coefficients C 1,2 are readily available in the literature 6,11,62 and are listed below in Eq. (20).…”

Section: Perturbatively Accessible Fixed Pointmentioning

confidence: 99%

Overscreened Kondo fixed point inS=1spin liquid

2013

View full text Add to dashboard Cite

We propose a possible realization of the overscreened Kondo impurity problem by a magnetic s = 1/2 impurity embedded in a two-dimensional S = 1 U (1) spin liquid with a Fermi surface. This problem contains an interesting interplay between non-Fermi-liquid behavior induced by a U (1) gauge field coupled to fermions and a non-Fermi-liquid fixed point in the overscreened Kondo problem. Using a large-N expansion together with an expansion in the dynamical exponent of the gauge field, we find that the coupling to the gauge field leads to weak but observable changes in the physical properties of the system at the overscreened Kondo fixed point. We discuss the extrapolation of this result to a physical case and argue that the realization of overscreened Kondo physics could lead to observations of effects due to gauge fields.

show abstract

Solution of the Multichannel Kondo Problem

Cited by 411 publications

References 16 publications

Thermodynamics of the anisotropic two-channel Kondo problem

Thermodynamics of the anisotropic two-channel Kondo problem

Dynamical properties of the Anderson impurity model within a diagrammatic pseudoparticle approach

Overscreened Kondo fixed point inS=1spin liquid

Contact Info

Product

Resources

About