Restoring Adiabatic State Transfer in Time-Modulated Non-Hermitian Systems.

Area of Science:

• Physics
• Quantum Mechanics
• Wave Phenomena

Background:

• Non-Hermitian systems exhibit exceptional points (EPs), spectral singularities reducing system dimensionality.
• Encircling EPs was proposed for symmetric mode switching, but typically yields asymmetric conversion due to failed adiabaticity.

Purpose of the Study:

• To theoretically demonstrate achievable adiabaticity and symmetric state transfer when encircling EPs in non-Hermitian systems.
• To overcome the inherent chirality in dynamical EP encirclement.

Main Methods:

• Investigating non-Hermitian systems with exceptional points.
• Theoretically analyzing trajectories in parameter space for EP encirclement.
• Identifying parameter space paths that maintain a real spectrum for the evolution operator.

Main Results:

• Demonstrated that specific trajectories around EPs enable adiabaticity.
• Achieved symmetric state transfer, contrary to previous findings of asymmetric mode conversion.
• Showcased a method to overcome the winding-direction-dependent chirality.

Conclusions:

• Symmetric adiabatic passage around EPs in non-Hermitian systems is feasible.
• The key lies in selecting parameter space trajectories yielding a real spectrum.
• This breakthrough advances wave manipulation protocols in quantum and classical physics.