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Non-Hermitian Topology in Multiterminal Superconducting Junctions
David Christian Ohnmacht1, Valentin Wilhelm1, Hannes Weisbrich1
1Universität Konstanz, Fachbereich Physik, D-78457 Konstanz, Germany.
Physical Review Letters
|May 2, 2025
Summary
Researchers explored non-Hermitian Hamiltonians in open quantum systems, focusing on topological phases in engineered superconducting Josephson junctions. They identified fragile and stable non-Hermitian topological phases arising from exceptional points.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Topological Materials
Background:
- Recent experiments in dissipation control offer insights into non-Hermitian Hamiltonians for open quantum systems.
- Topological characteristics in non-Hermitian systems are linked to unique degeneracies known as exceptional points.
Purpose of the Study:
- To investigate topological characteristics of Andreev bound states in multiterminal Josephson junctions.
- To explore non-Hermiticity induced by normal metal or ferromagnetic leads in engineered superconducting systems.
Main Methods:
- Studied Andreev bound states in multiterminal Josephson junctions.
- Introduced non-Hermiticity via normal metal or ferromagnetic leads.
- Investigated systems with varying synthetic dimensions and symmetries.
Main Results:
- Predicted the existence of non-Hermitian topological phases in engineered superconducting systems.
- Identified both fragile and stable topological phases.
- Demonstrated the role of exceptional points in the emergence of these topological phases.
Conclusions:
- Engineered superconducting systems can host non-Hermitian topological phases.
- The findings provide a pathway for designing novel topological quantum devices.
- Exceptional points are crucial for understanding topological properties in non-Hermitian systems.
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