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Non-Hermitian Boundary State Engineering in Anomalous Floquet Topological Insulators
Bastian Höckendorf1, Andreas Alvermann1, Holger Fehske1
1Institut für Physik, Universität Greifswald, Felix-Hausdorff-Str. 6, 17489 Greifswald, Germany.
Physical Review Letters
|November 26, 2019
Summary
We show that non-Hermitian Floquet insulators can lift bulk-boundary constraints in topological systems. This allows engineering of boundary states for enhanced and directional transport, demonstrated in photonic lattices.
Area of Science:
- Condensed Matter Physics
- Topological Materials
- Quantum Mechanics
Background:
- Hermitian topological systems enforce strict bulk-boundary correspondence.
- Topological properties dictate boundary transport values.
- This correspondence limits control over boundary phenomena.
Purpose of the Study:
- To demonstrate lifting of bulk-boundary constraints in non-Hermitian Floquet insulators.
- To explore independent modification of topological boundary states.
- To investigate tailored transport phenomena via non-Hermiticity.
Main Methods:
- Theoretical analysis of non-Hermitian Floquet insulators.
- Focus on anomalous topological phases.
- Exploration of non-Hermitian time-reversal symmetry.
Main Results:
- Non-Hermiticity enables independent engineering of boundary states.
- Topological nature of boundary states is preserved.
- Tailored helical and chiral transport achieved.
- Enhanced boundary transport relative to bulk motion observed.
Conclusions:
- Non-Hermitian Floquet insulators offer new control over topological boundary states.
- This provides pathways to engineer novel transport phenomena.
- Findings are experimentally relevant for photonic waveguide lattices.
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