Influence of Deterministic Attenuation and Amplification of Optical Signals on Entanglement and Distillation of Gaussian and Non-Gaussian Quantum States

We study general rules of entanglement dynamics for two-mode continuous variable states subjected to deterministic phase-insensitive attenuation and amplification. Since those processes inevitably involve quantum noises, we propose and solve the problem of finding noise levels destroying entanglement of Gaussian and non-Gaussian states. The amplification with power gain greater or equal than 2 necessarily leads to the total loss of entanglement. We consider nonGaussian states whose entanglement is robust to arbitrary signal attenuation and amplification provided the noise is restricted by some value close to the quantum limited operation. We calculate the lower bound on distillation rate of Bell states.