Entangled states of light and their robustness against photon absorption

We study how photon absorption losses degrade the bipartite entanglement of entangled states of light. We consider two questions: (i) What state contains the smallest average number of photons given a fixed amount of entanglement? (ii) What state is the most robust against photon absorption? We explain why the two-mode squeezed state is the answer to the first question but not quite to the second question.