2018/06/30 by Masaya Nakagawa, Norio Kawakami, Masahito Ueda · 3 citations
Physics and Astronomy · #cond-mat.quant-gas #cond-mat.str-el #quant-ph
paper · pdf · doi:10.1103/physrevlett.121.203001
published as Phys. Rev. Lett. 121, 203001 (2018) · 9 pages, 2 figures, published version
arxiv created 2018/11/14 · arxiv updated 2018/11/15
We investigate the Kondo effect in an open quantum system, motivated by recent experiments with ultracold alkaline-earth(-like) atoms. Because of inelastic collisions and the associated atom losses, this system is described by a complex-valued Kondo interaction and provides a non-Hermitian extension of the Kondo problem. We show that the non-Hermiticity induces anomalous reversion of renormalization-group flows which violate the g-theorem due to non-unitarity and produce a quantum phase transition unique to non-Hermiticity. Furthermore, we exactly solve the non-Hermitian Kondo Hamiltonian using a generalized Bethe ansatz method and find the critical line consistent with the renormalization-group flow.