Abstract
We investigate topological charge pumping in a system of interacting bosons in the tight-binding limit, described by the Rice-Mele model. An appropriate topological invariant for the many-body case is the change of polarization per pump cycle, which we compute for various interaction strengths from infinite-size matrix-product-state simulations. We 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 [Lohse et al., Nature Phys. 12, 350 (2016)]. Furthermore, we investigate the entanglement spectrum of the Rice-Mele model and argue that the quantized charge pumping is encoded in a winding of the spectral flow in the entanglement spectrum over a pump cycle.
Highlights
The experimental and theoretical investigation of topological states of matter is a key topic in condensed matter physics [1,2,3], ultracold quantum gases [4,5,6], and photonics [7,8]
III, we introduce the pump cycles studied in this paper and show how charge pumping remains quantized in the presence of interactions via the winding of polarization
We argue that the breakdown of a single-particle topological invariant could be demonstrated by measuring the quasimomentum distribution of each band and showing that the integral over this nα (k, θ ) and the known single-particle Berry curvature is not quantized
Summary
The experimental and theoretical investigation of topological states of matter is a key topic in condensed matter physics [1,2,3], ultracold quantum gases [4,5,6], and photonics [7,8]. We pursue two main goals: First, we reveal the breakdown of the single-particle interpretation in a parameter regime, where the charge pump remains topologically protected away from the limit of hardcore bosons. Measuring both the quasimomentum distribution function and the center-of-mass motion of the cloud as a measure of the quantization of charge pumping are sufficient to demonstrate this breakdown in an experiment.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
