Violations of Local Realism by Two Entangled N -Dimensional Systems Are Stronger than for Two Qubits
Dagomir Kaszlikowski, P. Gnaciński, Marek Żukowski, W. Miklaszewski, Anton Zeilinger · Physical Review Letters · 2000
Tests of local realism versus quantum mechanics based on Bell's inequality employ two entangled qubits. We investigate the general case of two entangled quantum systems defined in N-dimensional Hilbert spaces, or " quNits." Via a numerical linear optimization method we show that violations of local realism are stronger for two maximally entangled quNits ( 3</=N</=9) than for two qubits and that they increase with N. The two quNit measurements can be experimentally realized using entangled photons and unbiased multiport beam splitters.