'Quenched Exit Estimates and Ballisticity Conditions for Higher-Dimensional Random Walk in Random Environment'

'Quenched Exit Estimates and Ballisticity Conditions for Higher-Dimensional Random Walk in Random Environment'

Mon, 08/02/2010
15:45 		Alexander Drewitz (Technical University of Berlin) Stochastic Analysis Seminar Add to calendar Eagle House
'Quenched Exit Estimates and Ballisticity Conditions for Higher-Dimensional Random Walk in Random Environment'
 ABSTRACT "We give a short introduction to randomwalk in random environment(RWRE) and some open problems connected to RWRE.Then, in dimension larger than or equal to four we studyballisticity conditions and their interrelations. For this purpose, we dealwith a certain class of ballisticity conditions introduced by Sznitman anddenoted $ (T)_\gamma. $ It is known that they imply a ballistic behaviour of theRWRE and are equivalent for parameters $ \gamma \in (\gamma_d, 1), $ where$ \gamma_d $ is a constant depending on the dimension and taking values in theinterval $ (0.366, 0.388). $ The conditions $ (T)_\gamma $ are tightly interwovenwith quenched exit estimates.As a first main result we show that the conditions are infact equivalent for all parameters $ \gamma \in (0,1). $ As a second main result,we prove a conjecture by Sznitman concerning quenched exit estimates.Both results are based on techniques developed in a paperon slowdowns of RWRE by Noam Berger. (joint work with Alejandro Ramírez)"