Broken detailed balance in active biological systems
Measuring and quantifying non-equilibrium dynamics is a major challenge in living systems, due to their many-body nature and the limited number of variables accessible in an experiment. We present a method to identify non-equilibrium dynamics based on broken detailed balance. Using this approach, we study active dynamics in flagella, primary cilia, and cytoskeletal networks. What information concerning the system’s non-equilibrium state can be extracted from detecting broken detailed balance? To answer this question, we develop a general, yet simple model of soft elastic networks with a heterogeneous distribution of activities, representing internal enzymatic force generation. With this model, we determine the scaling behavior of non-equilibrium dynamics, including the entropy production rate. Our results provide insight into how internal driving by enzymatic activity generates non-equilibrium dynamics on different length scales in biological assemblies.