Gain-Driven Discrete Breathers in PT-Symmetric Nonlinear Metamaterials

TL;DR

This paper explores PT-symmetric nonlinear magnetic metamaterials, demonstrating the formation of stable discrete breathers due to gain-loss balance, with potential implications for energy localization in metamaterials.

Contribution

It introduces a novel PT-symmetric nonlinear metamaterial model and shows the existence of long-lived stable discrete breathers resulting from gain-loss matching.

Findings

Transition from exact to broken PT-phase affects spectrum

Stable discrete breathers form below the lower band branch

Energy is nearly equally partitioned between gain and loss elements

Abstract

We introduce a one dimensional parity-time (PT)-symmetric nonlinear magnetic metamaterial consisted of split ring dimers having both gain and loss. When nonlinearity is absent we find a transition between an exact to a broken PT-phase; in the former the system features a two band gapped spectrum with shape determined by the gain and loss coefficients as well as the inter-unit coupling. In the presence of nonlinearity we show numerically that as a result of the gain/dissipation matching a novel type of long-lived stable discrete breathers can form below the lower branch of the band with no attenuation. In these localized modes the energy is almost equally partitioned between two adjacent split rings on the one with gain and the other one with loss.