Entanglement-breaking channels and entanglement sudden death

Abstract

The occurrence of entanglement sudden death in the evolution of a bipartite\nsystem depends on both the initial state and the channel responsible for the\nevolution. An extreme case is that of entanglement braking channels, which are\nchannels that acting on only one of the subsystems drives them to full\ndisentanglement regardless of the initial state. In general, one can find\ncertain combinations of initial states and channels acting on one or both\nsubsystems that can result in entanglement sudden death or not. Neither the\nchannel nor the initial state, but their combination, is responsible for this\neffect, but their combination. In this work we show that, in all cases, when\nentanglement sudden death occurs, the evolution can be mapped to that of an\neffective entanglement breaking channel on a modified initial state. Our\nresults allow to anticipate which states will suffer entanglement sudden death\nor not for a given evolution. An experiment with polarization entangled photons\ndemonstrates the utility of this result in a variety of cases.\n