2025/05/23 by Vinayak M. Kulkarni, Kulkarni, Vinayak M. · 1 voice · 1 citation
#cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.2505.17811
Periodic driving of correlated impurities can generate nonequilibrium steady states in which balanced gain-loss structures and exceptional points emerge without inserting non-Hermitian terms by hand. We show that coarse graining a driven, inversion-asymmetric Dirac impurity produces a PT-symmetric frozen steady-state kernel with spin-selective gain and loss. The correlated impurity is treated within slave-boson mean-field theory, where the gauge-invariant condensate amplitude r=|bc| sets the channel-projected control scale. Within this approximation, finite-drive impurity-sector exceptional points produce strong nonnormality and reorganize low-energy spectral diagnostics. The retarded spectra are interpreted as frozen channel-projected kernels, while physical occupations are constructed from the bath-controlled fluctuation-dissipation relation. The eigenmode lesser Green's function is used only as a nonthermal diagnostic. We identify a shifted Friedel-type resonance near omegaK approximately Re epsilontildexi and compare screened local-moment, mixed-valence, and free-orbital regimes using Schrieffer-Wolff and frozen Bethe-Ansatz-kernel screening-scale estimates. The latter is obtained from the logarithmic derivative of the two-body scattering kernel and matched to the positive antiferromagnetic screening channel; it is not an exact thermodynamic Bethe-Ansatz solution. The analysis distinguishes impurity-localized exceptional points, which can enhance the estimated Kondo screening scale, from bath- or reservoir-induced exceptional points, which need not do so.