  We show how a quantum walk can be implemented for the first time in a quantum
quincunx created via superconducting circuit quantum electrodynamics (QED), and
how interpolation from quantum to random walk is implemented by controllable
decoherence using a two resonator system. Direct control over the coin qubit is
difficult to achieve in either cavity or circuit QED, but we show that a
Hadamard coin flip can be effected via direct driving of the cavity, with the
result that the walker jumps between circles in phase space but still exhibits
quantum walk behavior over 15 steps.
