Topological charge pumping in the interacting bosonic Rice-Mele model*

In recent years, demonstrations of topological Thouless charge pumping have been performed with ultra-cold atoms. We discuss our recent work [1] investigating charge pumping in the Bosonic Rice-Mele model and verify that the charge pumping remains quantized as long as the pump cycle avoids the superfluid phase. In the limit of hardcore bosons, the quantized pumped charge can be understood from single-particle properties such as the integrated Berry curvature constructed from Bloch states, while this picture breaks down at finite interaction strengths. These two properties -- robust quantized charge transport in an interacting system of bosons and the breakdown of a single-particle invariant -- could both be measured with ultracold quantum gases extending a previous experiment [2]. We also relate the structure of the spectral flow of the entanglement spectrum to the properties of the charge pump.

[1] A.L.C. Hayward et al., arXiv:1810.07043 (2018)
[2] M. Lohse et al., Nature Phys. 12, 350 (2016)