title: Universal relations in the finite-size correction terms of two-dimensional Ising models.
abstract: Quite recently, Izmailian and Hu [Phys. Rev. Lett. 86, 5160 (2001)] studied the finite-size correction terms for the free energy per spin and the inverse correlation length of the critical two-dimensional Ising model. They obtained the universal amplitude ratio for the coefficients of two series. In this study we give a simple derivation of this universal relation; we do not use an explicit form of series expansion. Moreover, we show that the Izmailian and Hu's relation is reduced to a simple and exact relation between the free energy and the correlation length. This equation holds at any temperature and has the same form as the finite-size scaling.
authors.affiliation: Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan. okabe@phys.metro-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Okabe
authors.forename: N
authors.initials: N
authors.lastname: Kawashima