Area Law Behaviour of Mutual Information at Finite Temperature. (arXiv:1907.04817v1 [hep-th])

Entanglement entropy in free scalar field theory at its ground state is
dominated by an area law term. However, when mixed states are considered this
property ceases to exist. We show that in such cases the mutual information
obeys an "area law". The proportionality constant connecting the area to the
mutual information has an interesting dependence on the temperature. At
infinite temperature it tends to a finite value which coincides with the
classical calculation.

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