Topological sound in active-liquid metamaterials

By Anton Souslov, Benjamin C. van Zuiden, Denis Bartolo, V. Vitelli. Nature Physics, 2016

263 citations recorded by the source corpus.

Ensuring topological protection of the edge states in candidate topological insulators is complicated by the need to break time-reversal symmetry. Polar active liquids present an innovative solution to this problem, as a new metamaterial design shows. Liquids composed of self-propelled particles have been experimentally realized using molecular, colloidal or macroscopic constituents1,2,3,4,5. These active liquids can flow spontaneously even in the absence of an external drive6,7,8. Unlike spontaneous active flow9,10, the propagation of density waves in confined active liquids is not well explored. Here, we exploit a mapping between density waves on top of a chiral flow and electrons in a synthetic gauge field11,12 to lay out design principles for artificial structures termed topological active metamaterials. We design metamaterials that break time-reversal symmetry using lattices composed of annular channels filled with a spontaneously flowing active liquid. Such active metamaterials support topologically protected sound modes that propagate unidirectionally, without backscattering, along either sample edges or domain walls and despite overdamped particle dynamics. Our work illustrates how parity-symmetry breaking in metamaterial structure combined with microscopic irreversibility of active matter leads to novel functionalities that cannot be achieved using only passive materials.

Subfields: Biomedical Engineering, Cognitive Neuroscience, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/d8d3c9b18773c783aa8ab1a4694d1ee4f672793c

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomedical Engineering

1. V. Vitelli
2. M. Cristina Marchetti
3. M. Bowick

In Mechanical Engineering

1. Anton Souslov
2. M. Cristina Marchetti
3. M. Bowick

Citations in the corpus

• Topological acoustics (2022, unknown): “particles without using external drives [29].”
• Topological active matter (2020, methodology): “If one now fills the rings with self-propelled particles (instead of a passive fluid like air), the required flow arises spontaneously without motorizing the circulators: the microscopic particles themselves are motorized 45 !”