  We demonstrate that in a standard thermo-electric nanodevice the current and
heat flows are not only dictated by the temperature and potential gradient, but
also by the external action of a local quantum observer that controls the
coherence of the device. Depending on how and where the observation takes
place, the direction of heat and particle currents can be independently
controlled. In fact, we show that the current and heat flow in a quantum
material can go against the natural temperature and voltage gradients.
Dynamical quantum observation offers new possibilities for the control of
quantum transport far beyond classical thermal reservoirs. Through the concept
of local projections, we illustrate how we can create and directionality
control the injection of currents (electronic and heat) in nanodevices. This
scheme provides novel strategies to construct quantum devices with application
in thermoelectrics, spintronic injection, phononics, and sensing among others.
In particular, highly efficient and selective spin injection might be achieved
by local spin projection techniques.
