Bipartite Entanglement

Ingemar Bengtsson, Karol Życzkowski

Paolo Facchi

We introduce a potential of multipartite entanglement for a system of n qubits, as the average over all balanced bipartitions of a bipartite entanglement measure, the purity. We study in detail its expression and look for its minimizers, the maximally multipartite entangled states. They have a bipartite entanglement that does not depend on the bipartition and is maximal for all possible bipartitions. We investigate their structure and consider several examples for small n.

Maike Drieb-Schön, Florian Dreier, Wolfgang Lechner

We investigate bipartite entanglement and prove that in constrained energy subspaces, the entanglement spectra of multiple bipartitions are the same across the whole subspace. We show that in quantum many-body systems the bipartite entanglement entropy is affected in such a way that it forms "bundles" under unitary time evolution. Leveraging the structure of the subspace, we present methods to verify whether the entanglement spectrum of two bipartitions is identical throughout the entire subspace. For the subspace defined by the parity embedding, we further provide an algorithm that can determine this in polynomial time.

Songbo Xie

Haiqing Huang, Irfan Ahmed, Ahmed Ali +3 more

Abstract We study the relations between the average bipartite entanglement and the N-partite length of correlation. We show that the N-partite length of correlation can completely determine the average bipartite entanglement for two and three-qubits. For four-, five- and six-qubit systems, the N-partite correlation functions may not determine the average bipartite entanglement. These results are novel and promising for pure state.

Fabio Benatti