The Vanishing of Excess Heat for Nonequilibrium Processes Reaching Zero Ambient Temperature

Close-to-equilibrium heat capacity

“…It is worth remembering that the 'Law' knows exceptions; equilibrium systems with highly degenerate ground states may not satisfy it, [28]. In recent work, [7,12], an extended Third Law was derived where the extension covers nonequilibrium jump processes: the nonequilibrium heat capacity vanishes at zero ambient temperature if the quasipotential remains bounded (in addition to having a nondegenerate zero-temperature regime for its static fluctuations). Here we show that in the McLennanregime, W and hence the quasipotential V ML = E − ⟨E⟩ ML + W always remains bounded as β ↑ ∞.…”

“…In recent papers [4][5][6][7][8], building on suggestions from steady-state thermodynamics [9][10][11], the notion of heat capacity was generalized to driven and active systems. There, a quasipotential captures the quasistatic excess heat, [3,7,12,13], which is the analogue of energy changes under detailed balance processes. One thus wonders whether that quasipotential also governs the occupation statistics of energy levels.…”