When a Bath Is Not Enough: State-Dependent Energy Injection and Nonmonotonic Dissipation in Cytoskeletal Matter

Living matter consumes energy to build and actuate dynamic protein machines, but the way energy enters these systems is often assumed to be externally imposed and independent of state. This review advances a unifying perspective, that across diverse cytoskeletal active matter, energy injection itself is state dependent, regulated by the mechanical and organizational configuration of the system, rather than acting as a fixed external bath. We synthesize recent experimental evidence, from excitable cortical waves to reconstituted actomyosin networks , showing that feedback between system state and energy input leads to nonmonotonic dissipation, selective energy routing, and relaxation-driven contractility. By organizing these findings within a common framework, we highlight how state-dependent energy injection challenges classical nonequilibrium assumptions and opens new questions for the design and control of active matter.