Topological symplectic Kondo effect

Abstract

Multiple conduction channels interacting with a quantum impurity -- a spin in the conventional ``multi-channel Kondo effect'' or a topological mesoscopic device (``topological Kondo effect'') -- has been proposed as a platform to realize anyonic quasi-particles. However, the above implementations require either perfect channel symmetry or the use of Majorana fermions. Here we propose a Majorana-free mesoscopic setup which implements the Kondo effect of the symplectic Lie group and can harbor emergent anyons (including Majorana fermions, Fibonacci anyons, and $\mathbb Z_3$ parafermions) even in the absence of perfect channel symmetry. In addition to the detailed prescription of the implementation, we present the strong coupling solution by mapping the model to the multi-channel Kondo effect associated to an internal $SU(2)$ symmetry and exploit conformal field theory (CFT) to predict the non-trivial scaling of a variety of observables, including conductance, as a function of temperature. This work does not only open the door for robust Kondo-based anyon platforms, but also sheds light on the physics of strongly correlated materials with competing order parameters.