Researchers Zixun Xu and Yuan Yao, affiliated with the University of California, Berkeley, have recently published a study in the journal Physical Review Letters that explores the behavior of Thouless pumps in quasi-periodic systems. Their work aims to clarify the extensions of these pumps in systems that are not purely periodic, which is a topic that has not been fully understood until now.
Thouless pumps are a type of topological pump that can transport particles in a quantized manner, meaning that the amount of transport is an integer multiple of a fundamental unit. In periodic systems, the behavior of Thouless pumps is well-established and is governed by Chern numbers or Wannier-center winding. However, in quasi-periodic systems, the behavior of these pumps is not as well understood.
In their study, Xu and Yao develop a general quantitative paradigm for bulk Thouless pumps in continuous models with spacetime quasi-periodicity. This paradigm is applicable to arbitrary spatial dimensions and is based on an emergent long wavelength effective potential. The researchers found that the bulk pumping in these systems is governed by the geometry of the quasi-Brillouin zone, which is a concept that generalizes the Brillouin zone to quasi-periodic systems.
One of the main results of the study is a universal relation between topological drifting and the geometry of the quasi-Brillouin zone. This relation allows for the direct calculation of Chern numbers from microscopic data, which is a significant advancement in the field. The researchers also conducted simulations of one- and two-dimensional continuous moiré-type spacetime quasi-periodic lattices, which exhibited stable, localized, directional drift in excellent agreement with the theory.
The practical applications of this research for the energy sector are not immediately clear, as the study is primarily theoretical in nature. However, the understanding of topological pumps and their behavior in different types of systems is an important area of research that could have implications for the development of new technologies in the future. For example, topological pumps could potentially be used to transport energy or information in a highly controlled and efficient manner. Further research will be needed to explore these possibilities and to determine the full range of practical applications for this exciting area of physics.
This article is based on research available at arXiv.