Relevance of Anisotropy in the Kondo Effect: Lessons From the Symplectic Case

Abstract

A Kondo model with symplectic symmetry was recently put forward as the effective low-energy theory of a superconducting-island device coupled to multiple leads. This model, which possesses non-Fermi liquid physics and effective anyons, was argued to belong to the class of topological Kondo effects. Here, we clarify the extent of stability of its exotic fixed point using perturbative and numerical renormalization group in conjunction with bosonization and conformal field theory. In contrast to previous claims, we show that asymmetry in the coupling to the leads destabilizes the non-Fermi liquid. Other destabilizing perturbations include asymmetry in the superconducting pairing or internal energy of the individual quantum dots in the island. Nevertheless, these perturbations all generate the same relevant operators. Thus, only a small number of couplings need to be tuned individually, and these can be selected according to experimental convenience. Our results highlight a common misconception that anisotropy in single-channel Kondo couplings is always irrelevant. As demonstrated, relevant terms will emerge whenever the group generators do not span the full space of impurity operators. This calls for a more detailed inspection of models that exhibit this property, such as large-spin impurities and SO(M) Kondo models.

arXiv comment28 pages, 7 figures, accepted version

References in corpus (49)

• The numerical renormalization group method for quantum impurity systems
• Observation of the two-channel Kondo effect
• Non-abelian symmetries in tensor networks: a quantum symmetry space approach
• Topological Kondo effect with Majorana fermions
• Two-channel Kondo effect and renormalization flow with macroscopic quantum charge states
• Tunable Quantum Criticality and Super-ballistic Transport in a `Charge' Kondo Circuit
• Multi-Terminal Coulomb-Majorana Junction
• Universal Fermi liquid crossover and quantum criticality in a mesoscopic device
• Supplementary material to Heavy electrons and the symplectic symmetry of spin
• Majorana-Klein hybridization in topological superconductor junctions
• Heavy electrons and the symplectic symmetry of spin
• Multi-channel Kondo impurity dynamics in a Majorana device
• Properties of anisotropic magnetic impurities on surfaces
• Generalized Wilson Chain for solving multichannel quantum impurity problems
• Symplectic N and time reversal in frustrated magnetism
• Exclusion Statistics in Conformal Field Theory -- generalized fermions and spinons for level-1 WZW theories
• X-Symbols for Non-Abelian Symmetries in Tensor Networks
• Simple Bosonization Solution of the 2-channel Kondo Model: I. Analytical Calculation of Finite-Size Crossover Spectrum
• Quantum simulation of an exotic quantum critical point in a two-site charge Kondo circuit
• Conductance fingerprint of Majorana fermions in the topological Kondo effect
• Anyons in Multichannel Kondo Systems
• Interleaved numerical renormalization group as an efficient multiband impurity solver
• Finite-Size Bosonization of 2-Channel Kondo Model: a Bridge between Numerical Renormalization Group and Conformal Field Theory
• Kondo-based Qubits for Topological Quantum Computation
• Nonequilibrium Transport through Double Quantum Dots: Exact Results near Quantum Critical Point
• Adaptive broadening to improve spectral resolution in the numerical renormalization group
• Bethe ansatz solution of the topological Kondo model
• Interplay of the Scaling Limit and the Renormalization Group: Implications for Symmetry Restoration
• Nonequilibrium Critical Behavior for Electron Tunneling through Quantum Dots in an Aharonov-Bohm Circuit
• Many-terminal Majorana island: from Topological to Multi-Channel Kondo Model
• Electron Teleportation in Multi-Terminal Majorana Islands: Statistical Transmutation and Fractional Quantum Conductance
• Exact nonequilibrium transport in the topological Kondo effect
• Thermodynamics of the Topological Kondo Model
• SO(5) non-Fermi liquid in a Coulomb box device
• Manipulating Non-Abelian Anyons in a Chiral Multichannel Kondo Model
• Parafermionic generalization of the topological Kondo effect
• Multi-impurity chiral Kondo model: correlation functions and anyon fusion rules
• ABCD of Kondo effect
• Two-Channel Kondo Physics in a Majorana Island Coupled to a Josephson Junction
• Poor man's scaling: anisotropic Kondo and Coqblin--Schrieffer models
• Topological symplectic Kondo effect
• Multichannel topological Kondo effect
• SO(5) critical point in a spin-flavor Kondo device -- Bosonization and refermionization solution
• Chiral numerical renormalization group
• Topological Kondo effect with spinful Majorana fermions
• Topological Quantum Computation on a Chiral Kondo Chain
• The topological Kondo model out of equilibrium
• Poor man's scaling and Lie algebras
• Poor man's scaling: $XYZ$ Coqblin--Schrieffer model revisited

Cited by in corpus (1)

• Topological ground state degeneracy of the two-channel Kondo lattice