Coherent State Distinguishability in Continuous Variable Quantum Cryptography
Christian Weedbrook, Mile Gu, Andrew M. Lance, Thomas Symul, Ping Koy Lam, Timothy C. Ralph
Abstract
We use the probability of error as a measure of distinguishability between two pure and two mixed symmetric coherent states in the context of continuous variable quantum cryptography. We show that the two mixed symmetric coherent states (in which the various components have the same real part) never give an eavesdropper more information than two pure coherent states.