Chimeras in SQUID Metamaterials

TL;DR

This paper demonstrates numerically that chimera states, characterized by coexisting synchronized and asynchronous clusters, can spontaneously form in one-dimensional SQUID metamaterials driven by an alternating magnetic field, with potential for experimental observation.

Contribution

It introduces the concept of chimera states in SQUID metamaterials and shows their spontaneous emergence under certain initial conditions through numerical simulations.

Findings

Chimera states appear for sufficiently strong initial excitations.

Chimera states exhibit relatively long lifetimes.

Potential for experimental detection with current setups.

Abstract

Regular lattices comprising superconducting quantum interference devices (SQUIDs) form magnetic metamaterials exhibiting extraordinary properties, including tunability, dynamic multistability, and negative magnetic permeability. The SQUIDs in a metamaterial interact through nonlocal, magnetic dipole-dipole forces that makes it possible for counter-intuitive dynamic states referred to as chimera states to appear; the latter feature clusters of SQUIDs with synchronous dynamics which coexist with clusters exhibiting asynchronous behavior. The spontaneous appearance of chimera states is demonstrated numerically for one-dimensional SQUID metamaterials driven by an alternating magnetic field in which the fluxes threading the SQUID rings are randomly initialized; then, chimera states appear generically for sufficiently strong initial excitations, which exhibit relatively long lifetimes. The synchronization and metastability levels of the chimera states are discussed in terms of appropriate measures. Given that both one- and two-dimensional SQUID metamaterials have been already fabricated and investigated in the laboratory, the presence of a chimera state could in principle be detected with presently available experimental setups.