Kondo effect of Laughlin quasiparticles

Y. Komijani, P. Simon, I. Affleck, Orbital Kondo effect in fractional quantum Hall systems, Phys. Rev. B 92, 075301 (2015).

• Can one have Kondo effect in fractional quantum Hall regime? In this work, we studied two anti-dots formed in a fractional quatum Hall liquid, coupled to the edge states on the two sides (left).
• We showed that this system forms an orbital Kondo effect in a Luttinger liquid, i.e. an extra Laughlin quasi-particle can sit on either of the two antidots and this forms a pseudo-spin, which is screened by the quasi-particles in the edge states.
• Experimentally, this system can be studied by measuring the conductance between the two edge states, backscattered via the anti-dots. It turns out that in this geometry backscattered conductance probes the dynamical spin susceptibility of the spin in the Kondo regime.
• The latter is known to have divergences in the weak-coupling regime. Using a Bloch equation (memory function) technique we resume a series of diagrams that allows us to remedy this divergence and make predictions for the exponents of the conductance vs. temperature (right).