  The D-wave processor is a partially controllable open quantum system which
exchanges energy with its surrounding environment (in the form of heat) and
with the external time dependent control fields (in the form of work). Despite
being rarely thought as such, it is a thermodynamic machine. Here we
investigate the properties of the D-Wave quantum annealers from a
thermodynamical perspective. We performed a number of reverse-annealing
experiments on the D-Wave 2000Q via the open access cloud server Leap, with the
aim of understanding what type of thermal operation the machine performs, and
quantifying the degree of dissipation that accompanies it, as well as the
amount of heat and work that it exchanges. The latter is a challenging task in
view of the fact that one can experimentally access only the overall energy
change occurring in the processor, (which is the sum of heat and work it
receives). However, recent results of non-equilibrium thermodynamics(namely,
the fluctuation theorem and the thermodynamic uncertainty relations), allow to
calculate lower bounds on the average entropy production (which quantifies the
degree of dissipation) as well as the average heat and work exchanges. The
analysis of the collected experimental data shows that 1) in a reverse
annealing process the D-Wave processor works as a thermal accelerator and 2)
its evolution involves an increasing amount of dissipation with increasing
transverse field.
