Demonstration of a two-dimensional -symmetric crystal

Area of Science:

• Quantum mechanics
• Photonics
• Condensed matter physics

Background:

• Parity-time (PT)-symmetry allows non-Hermitian systems to have real eigenvalues.
• PT-symmetry has been experimentally verified in 1D photonic systems.
• A 2D experimental platform for PT-symmetry remained elusive.

Purpose of the Study:

• To devise and experimentally realize a 2D PT-symmetric system.
• To investigate topological phase transitions in 2D non-Hermitian systems.
• To explore the emergence of topological mid-gap edge states.

Main Methods:

• Designed a 2D photonic waveguide lattice.
• Engineered a specific refractive index landscape.
• Incorporated alternating loss within the lattice.

Main Results:

• Successfully created a 2D PT-symmetric photonic system.
• Demonstrated a non-Hermitian 2D topological phase transition.
• Observed the emergence of topological mid-gap edge states.

Conclusions:

• The developed 2D PT-symmetric system is a viable platform for studying non-Hermitian physics.
• This work opens new avenues for exploring topological phenomena in 2D non-Hermitian systems.
• The findings have implications for novel photonic devices and quantum simulations.