Chiral numerical renormalization group

The interplay between the Kondo screening of quantum impurities (by electronic channels to which they couple) and interimpurity RKKY interactions (mediated by same channels) has been extensively studied. However, effect unidirectional (e.g., chiral or helical edge modes 2D topological materials) greatly restrict mediated interactions, only more recently come under scrutiny, it can drastically alter physics. Here we take Wilson's numerical renormalization group (NRG), most established method for treating impurity models, extend systems consisting two coupled at different locations channel(s). This is challenging due incompatibility unidirectionality with one main ingredients in NRG -- mapping channel(s) a Wilson chain tight-binding end hopping amplitudes decay exponentially distance. We bridge this gap introducing "Wilson ladder" chains, demonstrate that construction successfully captures channel(s), as well distance impurities. use order study single channel, showing all local properties thermodynamic quantities are indifferent distance, correspond separate single-impurity models. Extensions and/or possible.