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Observation of Nonlinear Exceptional Points with a Complete Basis in Dynamics
Kai Bai1, Tian-Rui Liu1, Liang Fang1
1Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China.
Physical Review Letters
|March 1, 2024
Summary
Researchers experimentally demonstrated nonlinear exceptional points (NEPs) in coupled circuit resonators. This work shows NEPs retain a complete eigenbasis, unlike linear exceptional points, opening new application possibilities.
Area of Science:
- Physics
- Nonlinear Dynamics
- Quantum Mechanics
Background:
- Exceptional points (EPs) are singularities in the complex eigenvalue spectrum of non-Hermitian systems.
- Nonlinearity and non-Hermiticity are recently combined to explore nonlinear EPs (NEPs).
- NEPs offer potential advantages over linear EPs, such as maintaining eigenbasis completeness.
Purpose of the Study:
- To experimentally demonstrate a nonlinear exceptional point (NEP).
- To investigate the properties of NEPs, specifically eigenfrequency response and eigenbasis completeness.
Main Methods:
- Utilized two non-Hermitian coupled circuit resonators.
- Incorporated a nonlinear saturable gain into the system.
- Analyzed the system's eigenfrequency response to perturbations at the NEP.
Main Results:
- Achieved the first direct experimental demonstration of a NEP.
- Observed a third-order root law in the eigenfrequency response to perturbations at the NEP.
- Confirmed that the eigenbasis of the governing Hamiltonian remains complete at the NEP.
Conclusions:
- The experimental results validate the theoretical predictions of NEPs.
- Demonstrated that NEPs can retain eigenbasis completeness, a key feature distinguishing them from linear EPs.
- The findings open new avenues for utilizing NEPs in various applications.
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