  The immense scalability of continuous-variable cluster states motivates their
study as a platform for quantum computing, with fault tolerance possible given
sufficient squeezing and appropriately encoded qubits [Menicucci, PRL 112,
120504 (2014)]. Here, we expand the scope of that result by showing that
additional anti-squeezing has no effect on the fault-tolerance threshold,
removing the purity requirement for experimental continuous-variable
cluster-state quantum computing. We emphasize that the appropriate experimental
target for fault-tolerant applications is to directly measure 15-17 dB of
squeezing in the cluster state rather than the more conservative upper bound of
20.5 dB.
