



01232nas a2200157   4500008004100000245005300041210005300094260001500147490000800162520078900170100001800959700002100977700002100998700001801019856003701037       2011                        eng d00aEntanglement can completely defeat quantum noise0 aEntanglement can completely defeat quantum noise  c2011/12/150 v1073 a  We describe two quantum channels that individually cannot send any
information, even classical, without some chance of decoding error. But
together a single use of each channel can send quantum information perfectly
reliably. This proves that the zero-error classical capacity exhibits
superactivation, the extreme form of the superadditivity phenomenon in which
entangled inputs allow communication over zero capacity channels. But our
result is stronger still, as it even allows zero-error quantum communication
when the two channels are combined. Thus our result shows a new remarkable way
in which entanglement across two systems can be used to resist noise, in this
case perfectly. We also show a new form of superactivation by entanglement
shared between sender and receiver.
1 aChen, Jianxin1 aCubitt, Toby, S.1 aHarrow, Aram, W.1 aSmith, Graeme  uhttp://arxiv.org/abs/1109.0540v1