with Alejandro F. Ramírez (PUC Chile)
We consider random walks in i.i.d. elliptic random environments which are not uniformly elliptic. We introduce a computable condition in dimension d=2 and a general condition valid for dimensions d> 1 expressed in terms of the exit time from a box, which ensure that local trapping would not inhibit a ballistic behavior of the random walk. Furthermore, we prove that this general condition is sharp.
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