title: Finite-temperature critical behavior of mutual information.
abstract: We study mutual information for Renyi entropy of arbitrary index n, in interacting quantum systems at finite-temperature critical points, using high-temperature expansion, quantum Monte Carlo simulations and scaling theory. We find that, for n>1, the critical behavior is manifest at two temperatures T(c) and nT(c). For the XXZ model with Ising anisotropy, the coefficient of the area law has a t lnt singularity, whereas the subleading correction from corners has a logarithmic divergence, with a coefficient related to the exact results of Cardy and Peschel. For T<nT(c) there is a constant term associated with broken symmetries that jumps at both T(c) and nT(c), which can be understood in terms of a scaling function analogous to the boundary entropy of Affleck and Ludwig.
authors.affiliation: Physics Department, University of California, Davis, California 95616, USA.
authors.forename: Rajiv R P
authors.initials: RR
authors.lastname: Singh
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Hastings
authors.forename: Ann B
authors.initials: AB
authors.lastname: Kallin
authors.forename: Roger G
authors.initials: RG
authors.lastname: Melko