Noncrossing Approximation for the Anisotropic Kondo Model: Charge Fluctuations in a Quantum Box
arXiv:cond-mat/0110335 · doi:10.1103/PhysRevB.64.245338
Abstract
The noncrossing approximation (NCA) is generalized to the multi-channel Kondo-spin Hamiltonian with arbitrary anisotropic exchange couplings and an external magnetic field, and applied -- in the framework of Matveev's mapping -- to the charge fluctuations in a single-electron box at the Coulomb blockade. The temperature dependences of the charge step and the capacitance are calculated for a narrow point contact. At low temperatures and close to the degeneracy point, the capacitance line shape exhibits an approximate scaling with U/\sqrt{T}, where U is the deviation in gate voltage from the degeneracy point. This scaling relation is proposed as a sharp experimental diagnostic for the non-Fermi-liquid physics of the system at low temperatures. Both the reliability and shortcomings of the Kondo NCA are discussed in detail. Through comparison with poor-man's scaling, we are able to pinpoint the omission of particle-particle processes as the origin of the NCA flaws. An extended diagrammatic scheme is devised to amend the NCA flaws.
21 pages, 16 figures
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Cited by in corpus (10)
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- Dynamical Properties of the Anderson Impurity Model within a Diagrammatic Pseudoparticle Approach
- Enhancement of the Two-channel Kondo Effect in Single-Electron boxes
- Two-channel Kondo tunneling in triple quantum dot
- Measuring Luttinger Liquid Correlations from Charge Fluctuations in a Nanoscale Structure
- Conserving many body approach to the fully screened, infinite U Anderson model
- Current Characteristics of the Single-Electron Transistor at the Degeneracy Point
- Two channel orbital Kondo effect in quantum dot with SO(n) symmetry
- A fully controllable Kondo system: Coupling a flux qubit and an ultracold Fermi gas