Transport in spinful non-Hermitian gauge lattices

Abstract

We extend the generalized transfer-matrix method introduced in [H. Ghaemi-Dizicheh, Phys.\ Rev.\ B \textbf{107}, 125155 (2023)] to one-dimensional spinful non-Hermitian tight-binding lattices with matrix-valued Abelian and non-Abelian gauge couplings. We derive a minimal channel-resolved transfer matrix and identify its eigenvalues with the generalized Bloch factors. The same transfer matrix determines the periodic- and open-boundary spectra, generalized Brillouin zone, skin localization, and finite-sample scattering conditions. In the Abelian limit, the model separates into fixed spin sectors, yielding exact spectral results and closed finite-length transport expressions in terms of Chebyshev polynomials. These results reveal bipolar spin-dependent skin localization and distinguish the reciprocal hopping scale, which governs poles, zeros, and reflectionlessness, from the directed-amplification factor controlling transmission asymmetry, transparency, and invisibility. For non-Abelian gauge fields, noncommuting link matrices coherently mix the spin sectors, such that four transfer eigenmodes jointly determine the non-Bloch spectrum and transport eigenchannels. We show that this mixing produces spin-hybridized lasing and coherent-perfect-absorption channels, Zeeman-tunable lasing thresholds, and direction-dependent reflectionless transport accompanied by pronounced spin conversion. The resulting boundary-condition criteria describe lasing, coherent perfect absorption, reflectionlessness, transparency, and invisibility, while identifying spin polarization and conversion as experimentally accessible signatures that distinguish Abelian from non-Abelian non-Hermitian transport.