Observation of two-particle Aharonov-Bohm interference

\textit{Nature} \textbf{448}, 333-337 (19 July 2007) We report the first observation of quantum interference between two independent {\&} non-interacting electrons in a unique interferometer proposed by Yurke et. al. [1] {\&} Samuelsson et. al. [2]. The interference fringes were observed only in the joint probability of electrons arrival at two different drains; hence being the quantum analogue to the Hanbury Brown {\&} Twiss (HBT) experiment with classical waves [3]. This, sought after, counter intuitive effect, is a direct result of the quantum exchange statistics of identical quantum particles. Our observation is a signature of orbital entanglement between two independent electrons, even tough they never interacted with each other. [1] B. Yurke {\&} D. Stoler, Phys. Rev. A46, 2229-2234 (1992) [2] P. Samuelsson, E. V. Sukhorukov {\&} M. Buttiker, Phys. Rev. Lett. 92, 02685 (2004). [3] R. Hanbury Brown {\&} R. Q. Twiss, Phil. Mag. 45, 663-682 (1954).