Shannon and von Neumann entropies of multi-qubit Schrödinger's cat states.

Using IBM's publicly accessible quantum computers, we have analyzed the entropies of Schrödinger's cat states, which have the form = (1/2) [|0 0 0⋯0〉 + |1 1 1⋯1〉]. We have obtained the average Shannon entropy of the distribution over measurement outcomes from 75 runs of 8192 shots, for each of the numbers of entangled qubits, on each of the quantum computers tested. For the distribution over N fault-free measurements on pure cat states, would approach one as N → ∞, independent of the number of qubits; but we have found that varies nearly linearly with the number of qubits .