Abstract
Under the assumption of an identity determining the free energy of a state of a statistical mechanical system relative to a given equilibrium state by means of the relative entropy, it is shown: first, that there is in any physically definable convex set of states a unique state of minimum free energy measured relative to a given equilibrium state; second, that if a state has finite free energy relative to an equilibrium state, then the set of its time translates is a weakly relatively compact set; and third, that a unique perturbed equilibrium state exists following a change in Hamiltonian that is bounded below.
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Donald, M.J. Free energy and the relative entropy. J Stat Phys 49, 81–87 (1987). https://doi.org/10.1007/BF01009955
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DOI: https://doi.org/10.1007/BF01009955