|Dynamic correlations in the two-channel Kondo model:a numerical renormalization group study seen against symmetries |
Physics and Astronomy
|Anna Toth, TU Budapest|
1:30 PM Serin E385 - Note special day
We generalize the spectral sum rule preserving density matrix numerical renormalization group method (DMNRG) in such a way that it can make use of an arbitrary number of local compact Lie group symmetries of the quantum impurity system. As one of its applications we study the Green's functions of the highest-weight fields in the electron-hole symmetrical spin-half two-channel Kondo (2CK) model. We use a conformal field theory based scaling approach to predict the analytic properties of the various Green's functions in the vicinity of the 2CK fixed point and confirm these predictions by DMNRG calculations. We compute the universal scaling curves connecting the 2CK scaling regimes and the channel anisotropy or
magnetic field induced Fermi liquid scaling regimes. We argue that the boundaries of the various 2CK scaling regimes depend not only on the type of the perturbation but also on the operator investigated. In a small magnetic field, a universal resonance is observed in the local fermion's spectral function. The dominant superconducting instability is found in the composite superconducting channel.