Sublattice signatures of transitions in a P T -symmetric dimer lattice

Abstract

Lattice models with non-hermitian, parity and time-reversal (PT) symmetric Hamiltonians, realized most readily in coupled optical systems, have been intensely studied in the past few years. A PT -symmetric dimer lattice consists of dimers with intra-dimer coupling ν, inter-dimer coupling ν', and balanced gain and loss potentials ±iγ within each dimer. This model undergoes two independent transitions, namely a PT -breaking transition and a topological transition. We numerically and analytically investigate the signatures of these transitions in the time-evolution of states that are initially localized on the gain-site or the loss-site.