Critical destruction of the Kondo effect in a particle-hole asymmetric Bose-Fermi Anderson model

Bose-Fermi Kondo/Anderson models are effective Hamiltonians to describe the quantum criticality of strongly correlated metals, especially the beyond-Landau quantum criticality in heavy fermion metals [1]. We revisit the particle-hole asymmetric Bose-Fermi Anderson model with a power-law bosonic bath having a sub-ohmic exponent s < 1 and a power-law fermionic bath having a pseudogap exponent r > 0. Critical destruction of Kondo screening manifests in both the spin and charge channels. Earlier work on the Ising-anisotropic model with r < ½ [2] has identified three ranges of r and s in which the quantum critical behavior is bosonic, fermionic, or of mixed character. Here we present calculations for r > ½ using a quantum Monte Carlo method for both the spin-isotropic and Ising-anisotropic cases, and the numerical renormalization-group method for Ising anisotropy. We advance a consistent description of the quantum critical behavior differing from results recently obtained via an epsilon-expansion approach. Implications for the quantum criticality of Hubbard-like models are discussed.

[1] Q. Si, S. Rabello, S., K. Ingersent, and J. L. Smith, Nature 413, 804 (2001).
[2] J. H. Pixley, S. Kirchner, K. Ingersent, and Q. Si, Phys. Rev. B 88, 24511 (2013).