Ergostatting and Thermostatting at a Fixed Point

We propose a novel type of ergostats and thermostats for molecular dynamics simulations. A general class of active particle swarm models is considered, where any specific total energy (alternatively any specific temperature) can be provided at a fixed point of the evolution of the swarm. We identify the extended system feedback force of the Nos\'e - Hoover thermostat with the "internal energy" variable of active Brownian motion.