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Entanglement, correlations, and the energy gap in many-body quantum systems

Henry L. Haselgrove·Michael A. Nielsen·Tobias J. Osborne
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Abstract

What correlations are present in the ground state of a many-body Hamiltonian? We study the relationship between ground-state correlations, especially entanglement, and the energy gap between the ground and first excited states. We prove several general inequalities which show quantitatively that ground-state correlations between systems not directly coupled by the Hamiltonian necessarily imply a small energy gap.

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Henry L. Haselgrove, Michael A. Nielsen, Tobias J. Osborne. 2003-08-14. Entanglement, correlations, and the energy gap in many-body quantum systems. https://doi.org/10.1103/physreva.69.032303

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