Article 2026-04-22 under-review v1

Laughlin pumping assisted by surface acoustic waves

R
Renfei Wang Peking University
X
Xiao Liu Peking University
A
Adbhut Gupta Princeton University
K
Kirk Baldwin Princeton University
L
Loren Pfeiffer Princeton University
W
Wenfeng Zhang Peking University
R
Rui-Rui Du Peking University
M
Mansour Shayegan Princeton University
X
Xi Lin International Center for Quantum Materials, Peking University
Y
Ying-Hai Wu Huazhong University of Science and Technology
Y
Yang Liu Peking University

Abstract

The quantum Hall effect is a fascinating electrical transport phenomenon signified by precise quantization of Hall conductivity $\sigma_\mathrm{xy}$ and vanishing longitudinal conductivity $\sigma_\mathrm{xx}$. Laughlin proposed an elegant explanation in which adiabatic insertion of a flux tube pumps charge through the system. This analysis unveils the fundamental role of gauge invariance and provides a compelling argument about the fractional charge of fractional quantum Hall states. While it has been used extensively as a theoretical tool, a quantitative experimental investigation is lacking despite multiple attempts. Here we report successful realizations of Laughlin pumping in several integer and fractional quantum Hall states. One essential technical innovation is using surface acoustic waves to periodically clear the charges accumulated during the pumping process. Magnetic fluxes are inserted at a constant rate so there is no need to perform complicated data fitting. Furthermore, our setting can reliably extract $\sigma_\mathrm{xx}$ that is several orders of magnitude lower than the limit of conventional techniques. Effective energy gaps can be deduced from the temperature dependence of $\sigma_\mathrm{xx}$, which are drastically different from those provided by conventional transport data. This work not only brings a famous gedanken experiment to reality but also serves as a portal for many future investigations.

Citation Information

@article{renfeiwang2026,
  title={Laughlin pumping assisted by surface acoustic waves},
  author={Renfei Wang and Xiao Liu and Adbhut Gupta and Kirk Baldwin and Loren Pfeiffer and Wenfeng Zhang and Rui-Rui Du and Mansour Shayegan and Xi Lin and Ying-Hai Wu and Yang Liu},
  journal={Nature Portfolio},
  year={2026},
  doi={https://doi.org/10.21203/rs.3.rs-8849788/v1}
}
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