TY - JOUR T1 - Entanglement can completely defeat quantum noise JF - Physical Review Letters Y1 - 2011 A1 - Jianxin Chen A1 - Toby S. Cubitt A1 - Aram W. Harrow A1 - Graeme Smith AB - 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. VL - 107 UR - http://arxiv.org/abs/1109.0540v1 CP - 25 J1 - Phys. Rev. Lett. U5 - 10.1103/PhysRevLett.107.250504 ER -