Writing in Nature, researchers describe the first-time observation of ‘self-organized criticality’ in a controlled laboratory experiment. Complex systems exist in mathematics and physics, but also occur in nature and society. The concept of self-organized criticality claims that without external input, complex systems in non-equilibrium tend to develop into a critical state far away from a stable equilibrium. That way, they reinforce their own non-equilibrium.
Systems that are at first glance quite different, like the dissemination of information in social networks or the spread of fire or disease, may have similar characteristics. One example is an avalanche-like behaviour that reinforces itself instead of coming to a standstill. However, these complex systems are very difficult to study under controlled lab conditions.
For the first time, researchers from the European Centre for Quantum Sciences (CESQ) in Strasbourg, in collaboration with researchers from the universities of Cologne and Heidelberg and the California Institute of Technology, have succeeded in observing the most important features of self-organized criticality in a controlled experiment—including universal avalanche behavior.