Scientists find that “perfect” systems may be surprisingly fragile

Perfection may not always be the best recipe for stability, especially in complex systems such as electrical grids, ecosystems, and advanced materials.

For years, researchers often worked from the assumption that networks should perform more reliably when their individual parts behave as similarly as possible. Real systems, however, rarely look that tidy. Power generators operate differently from one another, neurons vary in form and behavior, species occupy different roles in ecosystems, and the components inside engineered materials are not always perfectly uniform.

Physicists at Northwestern University now say those differences may sometimes be an advantage rather than a defect.