Robert König, Graeme Smith
IEEE Trans. Inf. Theory
Communication over a noisy quantum channel introduces errors in the transmission that must be corrected. A fundamental bound on quantum error correction is the quantum capacity, which quantifies the amount of quantum data that can be protected. We show theoretically that two quantum channels, each with a transmission capacity of zero, can have a nonzero capacity when used together. This unveils a rich structure in the theory of quantum communications, implying that the quantum capacity does not completely specify a channel's ability to transmit quantum information.
Robert König, Graeme Smith
IEEE Trans. Inf. Theory
Graeme Smith
ISIT 2008
Isaac Chuang, Andrew Cross, et al.
Journal of Mathematical Physics
Robert König, Graeme Smith
Physical Review Letters