Monday, August 27, 2012

1208.4962 (Jaegon Um et al.)

Entanglement versus mutual information in quantum spin chains    [PDF]

Jaegon Um, Hyunggyu Park, Haye Hinrichsen
The quantum entanglement $E$ of a bipartite quantum Ising chain is compared with the mutual information $I$ between the two parts after a local measurement of the classical spin configuration. As the model is conformally invariant, the entanglement measured in its ground state at the critical point is known to obey a certain scaling form. Surprisingly, the mutual information of classical spin configurations is found to obey the same scaling form, although with a different prefactor. Moreover, we find that mutual information and the entanglement obey the inequality $I\leq E$ in the ground state as well as in a dynamically evolving situation. This inequality holds for general bipartite systems in a pure state and can be proven using similar techniques as for Holevo's bound.
View original: http://arxiv.org/abs/1208.4962

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