We distinguish traditional implementations of autonomous Maxwell demons from related linear devices that were recently proposed, not relying on the notions measurements and feedback control. In both cases a current seems to flow against its spontaneous direction (imposed, e.g., by thermal or electric gradient) without external energy intake. However, in latter case, this inversion may only be a...

Dynamics of inelastic gases are studied within the framework of random collision processes. The corresponding Boltzmann equation with uniform collision rates is solved analytically for gases, impurities, and mixtures. Generally, the energy dissipation leads to a significant departure from the elastic case. Specifically, the velocity distributions have overpopulated high energy tails and differe...