Topological phase for entangled two-qubit states
Résumé
Entangled states play a crucial role in quantum physics, ranging from fundamental aspects to quantum information processing. We show here that entangled two-qubit states can also be used to characterize unambiguously the subtelty of the $SO(3)$ rotation group topology. The well known two distinct families of path in this group are put in one-to-one correspondance with cyclic evolutions of these entangled states, resulting on a $\pi$ phase difference. We propose a simple quantum opticsinterference experiment to demonstrate this topological phase shift.