 
Summary: Monte Carlo study of the Pure and Dilute
BaxterWu model
Nir Schreiber and Joan Adler
Physics Department, Technion, Israel Institute of Technology, Haifa, Israel, 32000
Abstract. We studied the pure and dilute BaxterWu (BW) models using the
LandauWang (LW) sampling method to calculate the DensityOfStates (DOS). We
rst used the exact result for the DOS of the Ising model to test our code. Then we
calculated the DOS of the dilute Ising model to obtaining a phase diagram, in good
agreement with previous studies. We calculated the energy distribution, together with
its rst, second and fourth moments, to give the specic heat and the energy fourth
order cumulant,better known as the Binder parameter, for the pure BW model. For
small samples, the energy distribution displayed a doubly peaked shape. Finite size
scaling analysis, however, showed a powerlaw decay of the right peak with the ratio
+ = = 0:531 0:048. The energy distribution yielded the expected BW = 2=3
critical exponent for the specic heat. The Binder parameter minimum appeared to
scale with lattice size L with an exponent B equal to the specic heat exponent. Its
location (temperature) showed a large correctiontoscaling term 1 = 0:248 0:025.
For the dilute BW model we found a clear crossover to a single peak in the energy
distribution even for small sizes and the expected = 0 was recovered.
PACS numbers: 05.10.Ln,05.50.+q,02.70.Rr
