Operating molecular transistors as heat pumps

We study heat transport in transistor-like devices composed of two reservoirs and a gate electrode, with a ballistic electronic one-dimensional system connected between the two reservoirs and interacting with a laser field. We derive in a simple way an equation for the heat flux in terms of the Floquet-Green operator of the system. As a case example, we investigate a two-level transistor and find that the laser field can produce a net heat flow out of either one of the reservoirs. The direction of this flow is determined by the gate voltage. We study numerically the dependence of this heat-pump on the relevant parameters of the system and show that there is a minimum temperature below which it does not operate.