  Recently a new form of quantum memory has been proposed. The storage medium
is an ensemble of electron spins, coupled to a stripline cavity and an
ancillary readout system. Theoretical studies suggest that the system should be
capable of storing numerous qubits within the ensemble, and an experimental
proof-of-concept has already been performed. Here we show that this minimal
architecture is not limited to storage but is in fact capable of full quantum
processing by employing measurement-based entanglement. The technique appears
to be remarkably robust against the anticipated dominant error types. The key
enabling component, namely a readout technology that non-destructively
determines "are there n photons in the cavity?", has already been realised
experimentally.
