  We consider a finite quantum system coupled to quasifree thermal reservoirs
at different temperatures. Under the assumptions of small coupling and
exponential decay of the reservoir correlation function, the large deviation
generating function of energy transport into the reservoirs is shown to be
analytic on a bounded set. Our method is different from the spectral
deformation technique which was employed recently in the study of
spin-boson-like models. As a corollary, we derive the Gallavotti-Cohen
fluctuation relation for the entropy production and a central limit theorem for
energy transport.
