Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

Area of Science:

• Quantum fluid dynamics
• Non-Hermitian physics
• Optics and photonics

Background:

• Exciton-polaritons are Bose-Einstein condensates formed from light and matter quasiparticles.
• Exceptional points (EPs) are unique degeneracies in non-Hermitian systems where eigenvalues and eigenvectors coalesce.
• Controlling quantum fluid properties like chirality and angular momentum is crucial for advanced optical applications.

Purpose of the Study:

• To demonstrate the generation of chiral vortex flows with fixed handedness in exciton-polariton quantum fluids.
• To investigate the role of exceptional points in creating these chiral modes.
• To explore the potential for generating tunable orbital angular momentum states.

Main Methods:

• Utilized an optically induced ring resonator for exciton polaritons.
• Drove two dipole modes of the non-Hermitian resonator into degeneracy to create a vortex.
• Precisely manipulated the resonator's potential to transition through an exceptional point.

Main Results:

• Successfully generated chiral vortex flows with fixed handedness in exciton-polariton quantum fluids.
• Observed the formation of a vortex state with a fixed orbital angular momentum (topological charge) near an EP.
• Demonstrated that manipulating system parameters near EPs is key to vortex generation.

Conclusions:

• Exceptional points provide a powerful mechanism for generating chiral vortex states in quantum fluids.
• This method offers precise control over the orbital angular momentum of exciton-polaritons.
• The findings open avenues for exploiting non-Hermitian physics in macroscopic quantum systems for optical applications.