Minor issue in O(3) Phi4 model
The scaling around criticality is fine (Heisenberg exponents), but the position of the critical point is off.
According to the literature (hasenbusch2001
, campostrini2002
, hasenbusch2011
) it should be at \beta=0.6862385(20)
for \lambda=4.5
, i.e. very close to that of the traditional Heisenberg model. However, it is found somewhere near \beta\approx 0.79
Looks like some issue with prefactors, influencing the relative couplings among Hamiltonian terms ... although there are not really many of them ...
Note: If \lambda
is made large, which corresponds to the Heisenberg limit, it looks like the correct Heisenberg critical point is recovered (as it should be).