Non-Hermitian Kondo Effect in Ultracold Alkaline-Earth Atoms Article Swipe

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physics bethe ansatz kondo model hamiltonian (control theory) hermitian matrix kondo effect renormalization group quantum mechanics ultracold atom quantum density matrix renormalization group quantum phase transition quantum critical point ansatz condensed matter physics quantum electrodynamics impurity mathematics mathematical optimization

Masaya Nakagawa , Norio Kawakami , Masahito Ueda ·

YOU? · · 2018 · Open Access · · DOI: https://doi.org/10.1103/physrevlett.121.203001 · OA: W2806230351

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 nonunitarity 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.