Complete absorption of topologically protected waves

Understand

Chiral edge states can transmit energy along imperfect interfaces in a topologically robust and unidirectional manner when protected by bulk-boundary correspondence.

• However, in continuum systems, the number of states at an interface can depend on boundary conditions.
• Here we design interfaces that host a net flux of the number of modes into a region, trapping incoming energy.
• As a realization, we present a model system of two topological fluids composed of counter-spinning particles, which are separated by a boundary that transitions from a fluid-fluid interface into a no-slip wall.