Entanglement and Decoherence

The interaction between entangled multi-particle systems with the environment leads to both local dynamics, associated with single-particle dissipation, diffusion, and decay, and to global dynamics, which may provoke the disappearance of entanglement at a finite time [1-6]. This phenomenon may occur even when single-particle decoherence is asymptotic in time, and constitutes yet another distinct trait of entanglement. It has been recently demonstrated, for two qubits under the action of independent environments, using an all-optical setup [7]. In this talk, some of the peculiarities of the dynamics of two-qubit entangled states undergoing decoherence will be reviewed, new features of the experiment realized at the Federal University of Rio de Janeiro [7] will be described, and the extension of these considerations to multi-particle entangled states will be discussed. Scaling laws for the decay of entanglement and its finite-time extinction in multi-particle systems will be discussed.