Scaling Theory vs Exact Numerical Results for Spinless Resonant Level Model

摘要

This paper studies the charge Kondo effect in the (spinless) interacting resonant level model (IRLM) by means of the continuous-time quantum Monte Carlo method. The charge Kondo effect may be relevant to certain Samarium compounds with peculiar heavy-fermion behavior. We use double expansion with respect to Coulomb interaction U_(fc) and hybridization V. Exact dynamics and thermodynamics of the IRLM are derived numerically for a wide range of U_(fc) with a given value of V. As U_(fc) becomes negative, a quantum critical point is found in excellent agreement with a simple scaling formula that deals with V in the lowest-order, and U_(fc) up to infinite order. As U_(fc) becomes positive and large, however, exact numerical results deviate from lower order scaling results. In particular, the renormalized hybridization increases monotonically with increasing U_(fc) in contrast with the scaling theory that suggests another quantum critical point.