Disciplinary publications from 2026
To Remember or Not to Remember
Does a system really have a memory—or are we just being fooled by noisy data? Many physical and biological processes are described using so-called Markov models, where the future depends only on the present and not on the past. Detecting when a system truly deviates from this "memoryless" behavior is therefore a fundamental challenge. The Theory of Complex Systems and Neurophysics Group (Benjamin Lindner) and the Statistical Physics and Nonlinear Dynamics Group (Igor Sokolov) examined a recently proposed test for identifying memory effects and asked a practical question: when does an apparent signal of memory reflect the system itself, and when is it simply the result of limited experimental data? Using a simple model system, they showed that the reliability of the test depends critically on the strength of the applied perturbation. Surprisingly, neither very weak nor very strong perturbations perform best. Instead, the most reliable results are obtained when the induced response is roughly the same size as the system's natural fluctuations. Curious how scientists test whether a system remembers its past? Explore their Physical Review EArticle!