  We revisit the evidence for quantum annealing in the D-Wave One device (DW1)
based on the study of random Ising instances. Using the probability
distributions of finding the ground states of such instances, previous work
found agreement with both simulated quantum annealing (SQA) and a classical
rotor model. Thus the DW1 ground state success probabilities are consistent
with both models, and a different measure is needed to distinguish the data and
the models. Here we consider measures that account for ground state degeneracy
and the distributions of excited states, and present evidence that for these
new measures neither SQA nor the classical rotor model correlate perfectly with
the DW1 experiments. We thus provide evidence that SQA and the classical rotor
model, both of which are classically efficient algorithms, do not
satisfactorily explain all the DW1 data. A complete model for the DW1 remains
an open problem. Using the same criteria we find that, on the other hand, SQA
and the classical rotor model correlate closely with each other. To explain
this we show that the rotor model can be derived as the semiclassical limit of
the spin-coherent states path integral. We also find differences in which set
of ground states is found by each method, though this feature is sensitive to
calibration errors of the DW1 device and to simulation parameters.
