Experimental verification of anisotropic invariance for three-qubit states

Abstract

We experimentally test the recently predicted anisotropic invariance properties of pure three-qubit states, via generation and measurement of polarization-path entangled three-qubit states. These properties do not require aligned reference frames, and can be determined from measurements on any two of the qubits. They have several applications, such as a universal ordering of pairwise quantum correlations, strong monogamy relations for Bell inequalities and quantum steering, and a complementarity relation for Bell nonlocality versus 3-tangle, some of which we also test. The results indicate that anisotropic invariance, together with the three-qubit Bloch vector lengths, provide a robust and complete set of invariants for such states under local unitary transformations.