Hermitian Nonlinear Wave Mixing Controlled by a PT-Symmetric Phase Transition

While non-Hermitian systems are normally constructed through incoherent coupling to a larger environment, recent works have shown that under certain conditions coherent couplings can be used to similar effect. We show that this new paradigm enables the behavior associated with the PT-symmetric phase of a non-Hermitian subsystem to control the containing Hermitian system through the coherent couplings. This is achieved in parametric nonlinear wave mixing where simultaneous second harmonic generation replaces the role of loss to induce non-Hermitian behavior that persists through a full exchange of power within the Hermitian system. These findings suggest a new approach for the engineering of dynamics where energy recovery and sustainability are of importance that could be of significance for photonics and laser science.

Automated summary

Recent research has shown that under certain conditions, coherent couplings can allow non-Hermitian subsystems to control containing Hermitian systems. This finding suggests a new approach for engineering dynamics, which could be of significance for photonics and laser science.