  We measure and quantify non-Markovian effects in IBM's Quantum Experience.
Specifically, we analyze the temporal correlations in a sequence of gates by
characterizing the performance of a gate conditioned on the gate that preceded
it. With this method, we estimate (i) the size of fluctuations in the
performance of a gate, i.e., errors due to non-Markovianity; (ii) the length of
the memory; and (iii) the total size of the memory. Our results strongly
indicate the presence of non-trivial non-Markovian effects in almost all gates
in the universal set. However, based on our findings, we discuss the potential
for cleaner computation by adequately accounting the non-Markovian nature of
the machine.
