Amplification of maximally-path-entangled number states
Girish Saran Agarwal, Subhash Chandra Chaturvedi, Amit Rai · Physical Review A · 2010
We examine the behavior of a non-Gaussian state like the maximally path-entangled number state commonly known as a $N00N$ state under phase-insensitive amplification. We derive an analytical result for the density matrix of the $N00N$ state for arbitrary gain of the amplifier. We consider cases of both symmetric and antisymmetric amplification of the two modes of the $N00N$ state. We quantitatively evaluate the loss of entanglement by the amplifier in terms of the logarithmic negativity parameter. We find that $N00N$ states are more robust than their Gaussian counterparts.