Topological effects in interacting Su-Schrieffer-Heeger chains

The Su-Schrieffer-Heeger (SSH) model [1] describes a linear chain with two distinct topological phases. We investigate the behavior of two interacting particles in this one-dimensional system by simulating the equivalent system of a single particle in a two-dimensional system. Even though the two particles repel each other, doublon states, where both particles are on the same lattice site, are possible. By performing time-dependent simulations, we investigate transitions between the two topological phases of the two-dimensional SSH-like system. We focus on the doublon and surface states and the relation between them.

Optical waveguides are a possible experimental realization of such two-dimensional systems [2]. Realizing energetically separated surface and doublon states would allow the routing of light along specific paths within a bundle of waveguides. This could lead to increased bandwidth for fiber-optic communications.

[1] W. P. Su, J. R. Schrieffer, A. J. Heeger, Solitons in Polyacetylene, Phys. Rev. Lett. 42, 1698 (1979)
[2] S. Stützer, Y. Plotnik, Y. Lumer, P. Titum, N. H. Lindner, M. Segev, M. C. Rechtsman, A. Szameit, Photonic topological Anderson insulators, Nature 560, 461 (2018)