  There are both practical and foundational motivations to consider the
thermodynamics of quantum systems at small scales. Here we address the issue of
autonomous quantum thermal machines that are tailored to achieve some specific
thermodynamic primitive, such as work extraction in the presence of a thermal
environment, while having minimal or no control from the macroscopic regime.
Beyond experimental implementations, this provides an arena in which to address
certain foundational aspects such as the role of coherence in thermodynamics,
the use of clock degrees of freedom and the simulation of local time-dependent
Hamiltonians in a particular quantum subsystem. For small-scale systems
additional issues arise. Firstly, it is not clear to what degree genuine
ordered thermodynamic work has been extracted, and secondly non-trivial
back-actions on the thermal machine must be accounted for. We find that both
these aspects can be resolved through a judicious choice of quantum
measurements that magnify thermodynamic properties up the ladder of
length-scales, while simultaneously stabilizing the quantum thermal machine.
Within this framework we show that thermodynamic reversibility is obtained in a
particular Zeno limit, and finally illustrate these concepts with a concrete
example involving spin-systems.
