1. response to defects in multi- and bipartite entanglement of isotropic quantum spin networks

Sudipto Singha Roy

Hanyang University, Korea

21 September 2018 Fri 11.30 am

                                      IBS Center for Theoretical Physics of Complex Systems (PCS), Administrative Office (B349), Theory Wing, 3rd floor

                                      Expo-ro 55, Yuseong-gu, Daejeon, South Korea, 34126 Tel: +82-42-878-8633                     


Resonating valence bond states have played a crucial role in the description of exotic phases in strongly correlated systems. It is therefore interesting to understand how quantum correlations are distributed among the constituents of these composite systems. In this regard, we consider an isotropic RVB network of spin-1/2 particles with a finite fraction of defects, where the corresponding wave function of the network is rotationally invariant under the action of local unitaries. By using quantum information-theoretic concepts like strong subadditivity of von Neumann entropy and approximate quantum telecloning, we prove analytically that in the presence of defects, caused by loss of a finite fraction of spins, the RVB network sustains genuine multisite entanglement, and at the same time may exhibit

finite moderate-range bipartite entanglement, in contrast to the case with no defects.