Generalized Constraints on Quantum Amplification
Uri Gavish, Bernard Yurke, Y. Imry · Physical Review Letters · 2004
We derive quantum constraints on the minimal amount of noise added in linear amplification involving input or output signals whose component operators do not necessarily have c-number commutators, as is the case for fermion currents. This is a generalization of constraints derived for the amplification of bosonic fields whose components possess c-number commutators.