2014/06/20 by Ilaria Siloi, Siloi, Ilaria, Filippo Troiani +1
Materials Science · Physics and Astronomy · #Magnetism in coordination complexes #Quantum and electron transport phenomena #Quantum many-body systems #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.48550/arxiv.1406.5427
arxiv created 2014/06/20 · arxiv updated 2014/06/23
We investigate multipartite entanglement in rings of arbitrary spins with antiferromagnetic interactions between nearest neighbors. In particular, we show that the non-degenerate ground state of rings formed by an even number (N) of spins is N-partite entangled, and exchange energy can thus be used as a multipartite-entanglement witness. We develop a general approach to compute the energy minima corresponding to biseparable states, and provide numerical results for a representative set of systems. Despite its global character, exchange energy also allows a spin-selective characterization of entanglement. In particular, in the presence of a magnetic defect, one can derive separability criteria for each individual spin, and use exchange energy for detecting entanglement between this and all the other spins.