  The Shannon capacity of a graph G is the maximum asymptotic rate at which
messages can be sent with zero probability of error through a noisy channel
with confusability graph G. This extensively studied graph parameter disregards
the fact that on atomic scales, Nature behaves in line with quantum mechanics.
Entanglement, arguably the most counterintuitive feature of the theory, turns
out to be a useful resource for communication across noisy channels. Recently,
Leung, Mancinska, Matthews, Ozols and Roy [Comm. Math. Phys. 311, 2012]
presented two examples of graphs whose Shannon capacity is strictly less than
the capacity attainable if the sender and receiver have entangled quantum
systems. Here we give new, possibly infinite, families of graphs for which the
entangled capacity exceeds the Shannon capacity.
