3 research outputs found
A study of logarithmic corrections and universal amplitude ratios in the two-dimensional 4-state Potts model
Monte Carlo (MC) and series expansion (SE) data for the energy, specific
heat, magnetization and susceptibility of the two-dimensional 4-state Potts
model in the vicinity of the critical point are analysed. The role of
logarithmic corrections is discussed and an approach is proposed in order to
account numerically for these corrections in the determination of critical
amplitudes. Accurate estimates of universal amplitude ratios ,
, and are given, which arouse
new questions with respect to previous works
Universal ratios of critical amplitudes in the Potts model universality class
Monte Carlo (MC) simulations and series expansions (SE) data for the energy,
specific heat, magnetization, and susceptibility of the three-state and
four-state Potts model and Baxter-Wu model on the square lattice are analyzed
in the vicinity of the critical point in order to estimate universal
combinations of critical amplitudes. We also form effective ratios of the
observables close to the critical point and analyze how they approach the
universal critical-amplitude ratios. In particular, using the duality relation,
we show analytically that for the Potts model with a number of states ,
the effective ratio of the energy critical amplitudes always approaches unity
linearly with respect to the reduced temperature. This fact leads to the
prediction of relations among the amplitudes of correction-to-scaling terms of
the specific heat in the low- and high-temperature phases. It is a common
belief that the four-state Potts and the Baxter-Wu model belong to the same
universality class. At the same time, the critical behavior of the four-state
Potts model is modified by logarithmic corrections while that of the Baxter-Wu
model is not. Numerical analysis shows that critical amplitude ratios are very
close for both models and, therefore, gives support to the hypothesis that the
critical behavior of both systems is described by the same renormalization
group fixed point.Comment: Talk presented at CCP 2008, Ouro Preto, 5-9 August 200