Unidirectional zero reflection as gauged parity-time symmetry

TL;DR

This paper introduces a new way to realize parity-time symmetry via gauge transformations, linking unidirectional zero reflection to gauged PT-symmetry, and demonstrates this experimentally in a microstrip system.

Contribution

It proposes a novel gauge transformation approach to establish PT-symmetry and connects unidirectional zero reflection with gauged PT-symmetry, supported by experimental validation.

Findings

Unidirectional zero reflection is always associated with gauged PT-symmetry.

Experimental demonstration using a microstrip transmission-line with magnetoelectric coupling.

Bianisotropy provides a simple route to realize PT-symmetry and explore exceptional point behavior.

Abstract

We introduce here the concept of establishing Parity-time symmetry through a gauge transformation involving a shift of the mirror plane for the Parity operation. The corresponding unitary transformation on the system's constitutive matrix allows us to generate and explore a family of equivalent Parity-time symmetric systems. We further derive that unidirectional zero reflection can always be associated with a gauged PT-symmetry and demonstrate this experimentally using a microstrip transmission-line with magnetoelectric coupling. This study allows us to use bianisotropy as a simple route to realize and explore exceptional point behaviour of PT-symmetric or generally non-Hermitian systems.