Autonomous conversion of information to work in quantum dots

Abstract

We consider an autonomous implementation of Maxwell's demon in a quantum dot architecture acting on a system without changing its number of particles or its energy. As in the original thought experiment, only the second law of thermodynamics is seemingly violated when disregarding the demon. The autonomous architecture allows us to compare descriptions in terms of information to a more traditional, thermoelectric characterization. Our detailed investigation of information-to-work conversion is based on fluctuation relations and second-law-like inequalities in addition to the average heat and charge currents. By introducing a time reversal on the level of individual electrons, we find a fluctuation relation that is not connected to any symmetry of the moment-generating function of heat and particle flows. Furthermore, we show how an effective Markovian master equation with broken detailed balance for the system alone can emerge from a full description, allowing for an investigation of the entropic cost associated with breaking detailed balance. Interestingly, while the entropic cost of performing a perfect measurement diverges, the entropic cost of breaking detailed balance does not. Our results connect various approaches and idealized scenarios found in the literature and can be tested experimentally with present-day technology.