The Central Limit Theorem for a model of discrete-time random walks on the lattice ޚ ν in a fluctuating random environment was proved for almost-all realizations of the space-time environment, for all ν > 1 in [BMP1] and for all ν ≥ 1 in [BBMP]. In [BMP1] it was proved that the random correction to the average of the random walk for ν ≥ 3 is finite. In the present paper we consider the cases ν = 1, 2 and prove the Central Limit Theorem as T → ∞ for the random correction to the first two cumulants. The rescaling factor for the average is T 1 4 for ν = 1 and (ln T ) 1 2 , for ν = 2; for the covariance it is T 1− ν 4 , ν = 1, 2.
IntroductionIn this paper we extend the main result of [BMP1] and [BBMP]. We consider a natural class of models of discrete-time random walks in random media on the lattice ޚ ν , ν = 1, 2, . . ., which evolve stochastically in time t. The environment is described by a field ξ = {ξ t (x) : x ∈ ޚ ν , t ∈ ޚ + } of random variables taking values in some finite set S. We denote by X t the particle position at time t.The random walk transition probabilities at time t iswhere P 0 is a probability distribution of an homogeneous random walk, and ε a small parameter. The function c represents the influence of the field on the evolution of the random walk. The interaction is "strictly local", i.e. confined to the place occupied by the particle at time t. The functions P 0 and c have compact support ("finite range" assumption).In general one assumes that the {ξ t (x), t ≥ 0}, x ∈ ޚ ν , are independent copies of an ergodic Markov chain. One can suppose a further local interaction of the