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Two-Point Versus Multipartite Entanglement in Quantum Phase Transitions

Alberto Anfossi·Paolo Giorda·Arianna Montorsi·Fabio Traversa
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Abstract

We analyze correlations between subsystems for an extended Hubbard model exactly solvable in one dimension, which exhibits a rich structure of quantum phase transitions (QPTs). The T=0 phase diagram is exactly reproduced by studying singularities of single-site entanglement. It is shown how comparison of the latter quantity and quantum mutual information allows one to recognize whether two-point or shared quantum correlations are responsible for each of the occurring QPTs. The method works in principle for any number D of degrees of freedom per site. As a by-product, we are providing a benchmark for direct measures of bipartite entanglement; in particular, here we discuss the role of negativity at the transition.

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Alberto Anfossi, Paolo Giorda, Arianna Montorsi, Fabio Traversa. 2005-08-30. Two-Point Versus Multipartite Entanglement in Quantum Phase Transitions. https://doi.org/10.1103/physrevlett.95.056402

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