The talk is dedicated to the topic of superactivation of the quantum
capacity of Gaussian channels. Smith et. al. have recently shown that
for two such channels with zero capacity Superactivation (0 + 0 > 0)
can be achieved. They provided explicit examples that make use of
active optical devices like squeezers.
In this talk I'll show that there is no superactivation for Gaussian
channels that are generated by passive means.