Kondo effect in a PT-symmetric non-Hermitian Hamiltonian
impurity models, Kondo effect, non-Hermitian Hamiltonians, PT symmetry, perturbative
renormalization group, non-Hermitian hopping.
The non-Hermitian physics along with strong correlations allows the appearance of new effects
in open quantum many-body systems with balanced gain and loss. In this work, we proposed a
generalized Anderson impurity model that presents the inclusion of non-Hermitian hopping terms between
an embedded quantum dot and two wires. Such non-Hermitian hopping terms are symmetric under the
combined action of parity (P) and time reversal (T ). We mapped the model in the regime of a localized
state occupied by a single electron leading to the PT -symmetric Kondo model . We analyzed the
interaction effects by applying the perturbative renormalization group approach. We found that the Kondo
effect persists if the couplings are below a critical value, which corresponds to the exceptional point of the
non-Hermitian Kondo interaction. We observed that in the regime of the spontaneous breaking of PT -
symmetry, the Kondo effect is suppressed and the low energy properties are governed by a local-moment
fixed point with zero conductance.