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New topological invariants in non-Hermitian systems
1Department of Physics, Indian Institute of Science, Bangalore-560012, India.
Summary
This review explores topological phases in non-Hermitian systems, detailing new topological invariants and unique phenomena like the skin effect. It highlights adaptations from Hermitian systems and potential applications in photonics.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Topological Materials
Background:
- Recent advancements in topological phases within non-Hermitian systems.
- Growing interest in theoretical and experimental investigations of these systems.
Purpose of the Study:
- To review key concepts of topological phases in non-Hermitian Hamiltonians.
- To discuss adaptations of topological invariants and the emergence of new ones.
- To explore unique phenomena and potential applications.
Main Methods:
- Adaptation of topological invariants from Hermitian to non-Hermitian systems.
- Analysis of new topological invariants arising from exceptional points and complex energy landscapes.
- Examination of modified adiabatic theory and bulk-boundary correspondence.
Main Results:
- Identification of new topological invariants, including winding numbers in the complex energy plane and half-integer Chern numbers.
- Observation of unique phenomena such as the skin effect and edge-selective topological polarizations.
- Demonstration of Kramers degeneracy in non-Hermitian systems.
Conclusions:
- Non-Hermitian systems exhibit unique topological properties distinct from their Hermitian counterparts.
- These properties, including the skin effect, offer novel avenues for topological phase research.
- Potential applications in photonic systems and future research directions are identified.
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