We establish the foundations of a nonequilibrium theory of quantum
thermodynamics for noninteracting open quantum systems strongly coupled to
their reservoirs within the framework of the nonequilibrium Green functions
(NEGF). The energy of the system and its coupling to the reservoirs are
controlled by a slow external time-dependent force treated to first order
beyond the quasistatic limit. We derive the four basic laws of thermodynamics
and characterize reversible transformations. Stochastic thermodynamics is
recovered in the weak coupling limit.Comment: 4 pages, 3 figures, Supplementary Material, v2: published versio