Coherent information of one-mode Gaussian channels—the general case of non-zero added classical noise
Kamil Brádler · Journal of Physics A Mathematical and Theoretical · 2015
We prove that whenever the coherent information of a one-mode Gaussian (OMG) channel is non-zero its supremum is achieved for the infinite input power. This is a well established fact for zero added classical noise, whereas the non-zero case has not been studied in detail. The presented analysis fills the gap for three canonical classes of OMG channels: the lossy, amplifying and additive classical noise channel class. For the remaining OMG channel classes the coherent information is known to vanish.