Finite temperature corrections in 2d integrable models

Petter Minnhagen, Beom Jun Kim, Petter Holme

Caselle, M., Hasenbusch, M.

We study the finite size corrections for the magnetization and the internal energy of the 2d Ising model in a magnetic field by using transfer matrix techniques. We compare these corrections with the functional form recently proposed by Delfino and LeClair-Mussardo for the finite temperature behaviour of one-point functions in integrable 2d quantum field theories. We find a perfect agreement between theoretical expectations and numerical results. Assuming the proposed functional form as an input in our analysis we obtain a relevant improvement in the precision of the continuum limit estimates of both quantities.

JUSSI TIMONEN, Yu Chen, R. Bullough

P Grinza, Antonio Rago A

A numerical study of finite temperature features of thermodynamical observables is performed for the lattice 2D Ising model. Our results support the conjecture that the finite size scaling analysis employed in the study of integrable perturbation of conformal field theory is still valid in the present case, where a non-integrable perturbation is considered.

R. Bullough, D. J. Pilling, JUSSI TIMONEN

Claudius Gros

The finite-size corrections in exact diagonalization studies of the one- and two-dimensional Hubbard model can be reduced systematically by a grand-canonical integration over boundary conditions. We present results for ground-state properties of the two-dimensional (2D) Hubbard model and an evaluation of the specific heat for the 1D and 2D Hubbard model. We find the reduction of the finite-size corrections to be substantial, especially in two dimensions. \textcopyright{} 1996 The American Physical Society.