symmetry phase transition of the trimer lattices with balanced gain and loss

School of Physics and Information Technology, Shaanxi Normal University - Xi'an 710119, PRC

^(a) xtxie@snnu.edu.cn

Received: 23 September 2017
Accepted: 7 December 2017

Abstract

We theoretical investigate the properties of the parity-time -symmetric trimer lattices in which each unit cell contains balanced gain and loss sites. The impacts of different parameters, such as intra-trimer couplings, inter-trimer couplings, and on-site energy, on the symmetry phase transition and topological phase transition of the trimer lattices are discussed. Our results show that the dynamics of the density distribution is significantly dependent on the difference between the on-site energy of the different sublattices. It is interesting that the topological edge states can be found only in the cases with broken symmetry phase. In principle, such trimer lattices may be established by a well-arranged optical waveguide array.