Page 20 - Fall2021

TOPOLOGICAL ACOUSTICS
effects of noise while maintaining the attractive sensitiv- ity properties associated with EPs.
Outlook
In this article, we have offered an overview of the powerful opportunities offered by topological concepts in acoustics to manipulate and control sound in fundamentally new ways. This emerging area of research takes inspiration from groundbreaking advances in condensed matter phys- ics, quantum mechanics, and photonics and leverages the properties of acoustic metamaterials to enable new forms of sound transport. Pseudospins emerging from geometrical asymmetries, external bias, spatiotemporal modulation, and nonlinearities can be leveraged to enable topological sound, benefiting a broad range of applications from sound trans- port robust to defects, noise, and disorder to multiplexing, information processing, data storage and manipulation, and sensing. We expect the field of topological acoustics to open disruptive directions for sound control, with an impact on basic science and applied technologies.
Acknowledgments
We are grateful to Ethan Wang and broadly to our col- laborators for numerous discussions on these topics. This work was supported by the National Science Foundation Emerging Frontiers in Research and Innovation (EFRI) program and the Department of Defense Multidisci- plinary University Research Initiatives (MURI) program.
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20 Acoustics Today • Fall 2021