Thermodynamic Speed Demon

Maxwell’s demon is a classic thought experiment challenging the statistical origins of the second law of thermodynamics. For over 150 years, it has sharpened our understanding of the links between work, entropy and dissipation, and the thermal cost of keeping information. In recent years, an important physical speed limit has been discovered, where  the Fisher information constrains the maximal energy dissipation rate of any system driven away from equilibrium. Here, we introduce a new demon that breaks this speed limit. Observing two chambers, the demon sorts driven particles by their diffusive speed. This sorting creates demonic gradients in heat release and the delivery of power to the system, and in the process violates the Fisher bound. As Maxwell's demon reincarnate, the speed demon not only sharpens our understanding of a recently discovered physical law but also opens broad paths for new applications in stochastic control.