摘要：The antiferromagnetic Ising model on the triangular lattice--a toy
model for geometric frustrations--is known to be notoriously difficult for
Monte Carlo simulations. Hereby I shall first introduce the conventional
Metropolis method and two versions of the Swendsen-Wang-type cluster
algorithms, and demonstrate (rigorously or numerically) that they are
non-ergodic at zero temperature. Then, I shall present three variants of the
recently developed worm algorithm. One of them is still non-ergodic at zero
temperature, while the ergodicity of the other two has been proved. Further,
the two ergodic methods only suffer minor critical slowing down.