  We implemented the refined Deutsch-Jozsa algorithm on a 3-bit nuclear
magnetic resonance quantum computer, which is the meaningful test of quantum
parallelism because qubits are entangled. All of the balanced and constant
functions were realized exactly. The results agree well with theoretical
predictions and clearly distinguish the balanced functions from constant
functions. Efficient refocusing schemes were proposed for the soft z-pulse and
J-coupling and it is proved that the thermal equilibrium state gives the same
results as the pure state for this algorithm.
