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Creating synthetic spaces for higher-order topological sound transport
Hui Chen1, Hongkuan Zhang2, Qian Wu1
1Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO, USA.
Nature Communications
|August 20, 2021
Summary
Researchers demonstrate acoustic topological pumping in higher-order topological insulators using synthetic dimensions. This breakthrough enables robust wave steering and exploration of topological matter in higher dimensions.
Area of Science:
- Acoustic topological insulators
- Synthetic dimensions in acoustics
- Higher-order topological matter
Background:
- Topological insulators are states of matter with unique conducting properties protected by topology.
- Synthetic dimensions have been explored in photonics and cold atoms, but not acoustics due to coupling limitations.
- Higher-order topological insulators exhibit novel edge and corner states.
Purpose of the Study:
- To theoretically formulate and experimentally demonstrate dynamic topological pumping in acoustic systems.
- To explore the use of synthetic dimensions for acoustic topological phenomena.
- To investigate higher-order topological transport and quantum Hall effects in acoustic crystals.
Main Methods:
- Development of acoustic crystals with strongly coupled acoustic cavities.
- Utilizing modulated channels to engineer synthetic dimensions.
- Calculation of first and second Chern numbers to characterize topological properties.
- Physical illustration of edge-bulk-edge and corner-bulk-corner transport in finite structures.
Main Results:
- Successful demonstration of one-dimensional (1D) and two-dimensional (2D) dynamic topological pumpings in acoustic systems.
- Observation of higher-order topological edge-bulk-edge and corner-bulk-corner transport.
- Delineation of 2D and four-dimensional (4D) quantum Hall effects.
- Demonstration of robustness against geometrical imperfections.
Conclusions:
- Synthetic dimensions offer a viable platform for realizing topological phenomena in acoustics.
- This work establishes acoustic topological insulators as a powerful tool for wave steering.
- Opens new avenues for exploring higher-order topological matter in dimensions four and beyond.
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