On the speed of Random Walks among Random Conductances

We consider random walk among random conductances where the conductance environment is shift invariant and ergodic. We study which moment conditions of the conductances guarantee speed zero of the random walk. We show that if there exists \alpha>1 such that E[log^\alpha({\omega}_e)]<\infty, then the random walk has speed zero. On the other hand, for each \alpha>1 we provide examples of random walks with non-zero speed and random walks for which the limiting speed does not exist that have E[log^\alpha({\omega}_e)]<\infty.