# Boundary-Driven Anomalous Spirals in Oscillatory Media

## TL;DR

This paper introduces a new class of boundary-driven anomalous spiral patterns in oscillatory media, characterized by wave sinks and non-monotonic wavefronts, which can be experimentally realized through gain modulation.

## Contribution

It identifies and characterizes a novel class of boundary-driven spiral patterns in the complex Landau-Ginzburg model, distinct from traditional spirals, with potential experimental applications.

## Key findings

- New boundary-driven spiral patterns identified
- Spirals act as wave sinks with non-monotonic wavefronts
- Potential for experimental realization in nonlinear optics

## Abstract

We study a heretofore ignored class of spiral patterns for oscillatory media as characterized by the complex Landau-Ginzburg model. These spirals emerge from modulating the growth rate as a function of $r$, thereby turning off the instability. These spirals are uniquely determined by matching to those outer conditions, lifting a degeneracy in the set of steady-state solutions of the original equations. Unlike the well-studied spiral which acts a wave source, has a simple core structure and is insensitive to the details of the boundary on which no-flux conditions are imposed, these new spirals are wave sinks, have non-monotonic wavefront curvature near the core, and can be patterned by the form of the spatial boundary. We predict that these anomalous spirals could be produced in nonlinear optics experiments via spatially modulating the gain of the medium.