Superexponential amplification, power blowup, and solitons sustained by non-Hermitian gauge potentials

TL;DR

This paper explores how non-Hermitian gauge potentials in a two-component system cause superexponential amplification, power blowup, and the formation of stable solitons, revealing novel phenomena in linear and nonlinear regimes.

Contribution

It introduces a new non-Hermitian gauge potential model and demonstrates its effects on wave amplification, power blowup, and soliton formation in nonlinear optical systems.

Findings

Superexponential convective amplification observed in linear regime.

Finite-distance power blowup and beam delocalization.

Formation of stable fundamental and dipole solitons with complex gauge fields.

Abstract

We introduce a continuous one-dimensional non-Hermitian matrix gauge potential and study its effect on dynamics of a two-component field. The model is emulated by a system of evanescently coupled nonlinear waveguides with distributed gain and losses. The considered gauge fields lead to a variety of unusual physical phenomena in both linear and nonlinear regimes. In the linear regime, the field may undergo superexponential convective amplification. A total power of an input Gaussian beam may exhibit a finite-distance blowup, which manifests itself in absolute delocalization of the beam at a finite propagation distance, where the amplitude of the field remains finite. The defocusing Kerr nonlinearity initially enhances superexponential amplification, while at larger distances it suppresses the growth of the total power. The focusing nonlinearity at small distances slows down the power growth and eventually leads to the development of the modulational instability. Complex periodic gauge fields lead to the formation of families of stable fundamental and dipole solitons.