title: Nonadditivity in quasiequilibrium states of spin systems with lattice distortion.
abstract: It is argued that a certain kind of short-range interacting system exhibits nonadditivity when several time scales are well separated. Under the condition of separated time scales, the system is described by the elastic spin model. We find that it is extensive but nonadditive, which is directly confirmed by the work measurement and also indicated by ensemble inequivalence. Further, we estimate the effective Hamiltonian for the spin variables, and it is clarified that the effective interaction is long ranged. Remarkably, the so-called Kac prescription, which is usually regarded as a mathematical operation to make the system extensive, naturally holds.
authors.affiliation: Department of Physics, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. mori@spin.phys.s.u-tokyo.ac.jp
authors.forename: Takashi
authors.initials: T
authors.lastname: Mori