Even with experiments still ongoing, quantum entanglement is most likely real. I think David Kaiser wouldn't suggest otherwise. There's a real nice section in

Even with experiments still ongoing, quantum entanglement is most likely real. I think David Kaiser wouldn't suggest otherwise. There's a real nice section in wikipedia re: the testing of quantum entanglement (see http://en.wikipedia.org/wiki/Quantum_entanglement http://en.wikipedia.org/wiki/Quantum_entanglement) "Systems which contain no entanglement are said to be separable. For 2-Qubit and Qubit-Qutrit systems (2 x 2 and 2 x 3 respectively) the simple Peres-Horodecki criterion provides both a necessary and a sufficient criterion for separability, and thus for detecting entanglement. However, for the general case, the criterion is merely a sufficient one for separability, as the problem becomes NP-hard.[59][60] A numerical approach to the problem is suggested by Jon Magne Leinaas, Jan Myrheim and Eirik Ovrum in their paper "Geometrical aspects of entanglement".[61] Leinaas et al. offer a numerical approach, iteratively refining an estimated separable state towards the target state to be tested, and checking if the target state can indeed be reached. An implementation of the algorithm (including a built in Peres-Horodecki criterion testing) is brought in the "StateSeparator" web-app."