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Emerging (2+1)D Electrodynamics and Topological Instanton in Pseudo-Hermitian Two-Level Systems
Kuangyin Deng1, Ran Cheng1,2,3
1University of California, Department of Electrical and Computer Engineering, Riverside, California 92521, USA.
Physical Review Letters
|October 5, 2025
Summary
We uncovered a novel electrodynamical structure in pseudo-Hermitian systems. This structure, linked to spacetime instantons, differs significantly from the magnetic monopole behavior seen in Hermitian systems.
Area of Science:
- Quantum mechanics
- Condensed matter physics
- Electrodynamics
Background:
- Pseudo-Hermitian systems with real spectra are of interest.
- Berry curvature in Hermitian systems is analogous to a magnetic monopole.
- Understanding novel electrodynamical structures is crucial.
Purpose of the Study:
- To reveal a hidden electrodynamical structure in 2x2 pseudo-Hermitian systems.
- To investigate the nature of Berry curvature in these systems.
- To contrast findings with those in Hermitian systems.
Main Methods:
- Analysis of general 2x2 pseudo-Hermitian Hamiltonians.
- Mapping Berry curvature to electromagnetic fields.
- Investigating spacetime instanton properties.
Main Results:
- A 2+1-dimensional electromagnetic field emerges from the Berry curvature.
- This field arises from an artificial spacetime instanton, not a static magnetic field.
- The instanton possesses a topological charge quantifying magnetic flux jumps.
Conclusions:
- Pseudo-Hermitian systems exhibit unique electrodynamical structures.
- Spacetime instantons play a key role in quantizing Berry curvature.
- The findings are exemplified in antiferromagnetic magnons.
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