It is argued that the leading corrections to scaling for planar Ising models, which occur as analytic factors, arise from the quadratic terms of the nonlinear thermal and ordering fields (rather than from irrelevant variables). This yields ${{\ensuremath{\alpha}}_{\mathrm{eff}}}^{\ensuremath{'}}+2{\ensuremath{\beta}}_{\mathrm{eff}}+{{\ensuremath{\gamma}}_{\mathrm{eff}}}^{\ensuremath{'}}=2$ for the effective critical exponents, with
no leading corrections, and is confirmed by exact square-lattice results for arbitrary anisotropy
J1J2. For isotropic lattices the ratios of correction amplitudes and quadratic nonlinear-field terms appear universal.
We use heat bath dynamics to evaluate the dynamic critical exponent
z and the dynamic finite-size scaling function of an Ising model on square, planar triangular, and honeycomb lattices. We find convincing evidence that
z is universal and, by choosing an aspect ratio and a nonuniversal metric factor for the scaled time of each lattice, we can obtain a universal dynamic finite-size scaling function for the Ising model on the planar lattices. Our results suggest many interesting problems for further research.
We study the (analytic) finite-size corrections in the Ising model on the strip with free, fixed (++), and mixed boundary conditions. For fixed (++) boundary conditions, the spins are fixed to the same values on two sides of the strip. We find that subdominant finite-size corrections to scaling should be to the form a(p)/N(2p-1) for the free energy f(N) and b(p)/N(2p-1) for inverse correlation length ξ(N)(-1), with integer value of p. We investigate the set {a(p),b(p)} by exact evaluation and their changes upon varying anisotropy of coupling. We find that the amplitude ratios b(p)/a(p) remain constant upon varying coupling anisotropy. Such universal behavior is correctly reproduced by the conformal perturbative approach.