Journal of Statistical Mechanics: Theory and Experiment, 2014(4):P04011, IOP Publishing, 2014. Paper Website abstract bibtex
We study the analog of the "Kondo cloud" in the Resonant Level Model (RLM). The RLM is a solvable impurity model that arises as limits of several widely studied impurity models: the (anisotropic) Kondo model, the Anderson impurity model, and the interacting resonant level model. In all these systems, the impurity generates a length scale, which should show up in the structure of impurity-bath correlation functions as a function of distance from the impurity. For the RLM, we calculate this dependence explicitly and demonstrate the appearance of a length scale. The two-point impurity-bath correlator decays logarithmically at distances smaller than this length scale ("within the cloud") and decays as a power law at larger distancs ("outside the cloud"). We construct one-dimensional lattice realizations of the RLM with different geometries and show that this description of the screening cloud is valid for each geometry. We also characterize the impurity cloud using the behavior of the entanglement entropy of a region surrounding the impurity with the rest of the bath.