  We consider an autonomous implementation of Maxwell's demon in a quantum dot
architecture. 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 novel 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 to
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.
