  As has been shown elsewhere, a reasonable model of the loss of entanglement
or correlation that occurs in quantum computations is one which assumes that
they can effectively be predicted by a framework that presupposes the presence
of irreversibilities internal to the system. It is based on the
steepest-entropy-ascent principle and is used here to reproduce the behavior of
a controlled-PHASE gate in good agreement with experimental data. The results
show that the loss of entanglement predicted is related to the
irreversibilities in a nontrivial way, providing a possible alternative
approach that warrants exploration to that conventionally used to predict the
loss of entanglement. The results provide a means for understanding this loss
in quantum protocols from a nonequilibrium thermodynamic standpoint. This
framework permits the development of strategies for extending either the
maximum fidelity of the computation or the entanglement time.
