Entanglement Dynamics in Open Two-Qubit Systems via Diffusive Quantum Trajectories

We use quantum diffusive trajectories to prove that the time evolution of two-qubit entanglement under spontaneous emission can be fully characterized by optimalcontinuous monitoring. We analytically determine this optimal unraveling and derive a deterministic evolution equation for the system’s concurrence. Furthermore, we propose an experiment to monitor the entanglement dynamics in bipartite two-level systems and to determine the disentanglement time from a single trajectory.

http://prl.aps.org/abstract/PRL/v105/i21/e210502 

http://arxiv.org/abs/1006.1452