Topological pumping in non-Abelian synthetic gauge fields
Phys. Rev. B 113, 104315 – Published 27 March, 2026
DOI: https://doi.org/10.1103/dm79-94hr
Abstract
Topological pumping manifests quantized particle transport protected by band topology in adiabatically driven systems. To date, all previous implementations relied on Abelian gauge fields; the role of non-Abelian gauge fields in tailoring spin-resolved topological transport remains relatively unexplored. Here, we uncover a pseudospin-sublattice-locked bidirectional topological pumping phenomenon mediated by U(2) non-Abelian synthetic gauge fields. By extending the three-site Aubry-André-Harper model to the non-Abelian regime with noncommuting hopping matrices, we engineer a one-dimensional U(2) lattice model that can decouple into two subspaces, where each one hosts hybridized pseudospin states at different sublattices, forming three quasiflat bands with nonzero Chern numbers. These bands resist full spin polarization, enforcing pseudospin-sublattice-resolved pumping dynamics: pseudospin pairs on few sublattices evolve with antiparallel phase relationships, while those on the remaining sublattices synchronize, locking pumping directionality to specific sublattice-pseudospin-locked configurations. Experimentally, we realize this mechanism through time-modulated non-Abelian topolectrical circuits, where dynamical equations preserve exact isomorphism with the theoretical lattice model. Direct measurements of voltage dynamics reveal pseudospin-sublattice-locked pumping trajectories. Our work establishes non-Abelian synthetic gauge fields as a versatile tool for pseudospin-resolved topological control, possessing potential applications in spin-sublattice-selective topological transport.
