Broken symmetries in topological condensed matter systems have implications for the spectrum of Fermionic excitations confined on surfaces or topological defects. The Fermionic spectrum of confined (quasi2D)^{3}HeA consists of branches of chiral edge states. The negative energy states are related to the groundstate angular momentum,
We study how confinement transforms the chaotic dynamics of bulk microtubulebased active nematics into regular spatiotemporal patterns. For weak confinements in disks, multiple continuously nucleating and annihilating topological defects selforganize into persistent circular flows of either handedness. Increasing confinement strength leads to the emergence of distinct dynamics, in which the slow periodic nucleation of topological defects at the boundary is superimposed onto a fast procession of a pair of defects. A defect pair migrates toward the confinement core over multiple rotation cycles, while the associated nematic director field evolves from a distinct double spiral toward a nearly circularly symmetric configuration. The collapse of the defect orbits is punctuated by another boundarylocalized nucleation event, that sets up longterm doubly periodic dynamics. Comparing experimental data to a theoretical model of an active nematic reveals that theory captures the fast procession of a pair of
 Award ID(s):
 1810077
 NSFPAR ID:
 10086624
 Publisher / Repository:
 Proceedings of the National Academy of Sciences
 Date Published:
 Journal Name:
 Proceedings of the National Academy of Sciences
 Volume:
 116
 Issue:
 11
 ISSN:
 00278424
 Page Range / eLocation ID:
 p. 47884797
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
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