“Our review article brings together recent findings on the role of noise in the dynamics of excitable systems.”

Our review article brings together recent findings on the role of noise in the dynamics of excitable systems. Excitability is a phenomenon often observed in a variety of systems studied in physics, chemistry, and biology. For example, excitability in biological systems can be observed on different scales, ranging from cell membrane ion channels and sub-cellular networks to single cells and cell assemblies and tissues. Examples in physics include the dynamics of semiconductor nanostructures and lasers. Taking fluctuations into consideration is essential for a realistic modeling, and this has led to a large interdisciplinary interest in the topic of noise-perturbed dynamics of excitable systems.

Standard methods of statistical physics near equilibrium—linearization around equilibrium, Onsager relations—are insufficient to describe the physics of excitable systems operating far from thermodynamic equilibrium. Besides many numerical simulation results, our paper discusses novel analytical approaches to the steady-state and spectral statistics of excitable systems using Markovian and Non-Markovian models.

Usually fluctuations and noise are associated with disorder, and our intuition tells us that "no noise is good noise." On the contrary, our review underlines a general principle under which fluctuations may result in counter-intuitive effects, where an optimal amount of noise leads to improved performance of a system. These effects include emergence of noise-induced rhythmic activity, noise-enhanced signal transmission, and noise-induced structures in excitable media. We study these effects using generic models and theoretical predictions that are applicable to a wide range of systems in physics, chemistry, and biology.