  We provide an alternative interpretation of recently published experimental
results that were represented as demonstrating entanglement between two
macroscopic quantum Josephson oscillators. We model the experimental system
using the well-established classical equivalent circuit of a resistively and
capacitively shunted junction. Simulation results are used to generate the
corresponding density matrix, which is strikingly similar to the previously
published matrix that has been declared to be an unambiguous demonstration of
quantum entanglement. Since our data are generated by a classical model, we
therefore submit that state tomography cannot be used to determine absolutely
whether or not quantum entanglement has taken place. Analytical arguments are
given for why the classical analysis provides an adequate explanation of the
experimental results.
