Deviation of ergodic averages for substitution dynamical systems with eigenvalues of modulus one

Abstract. Deviation of ergodic sums is studied for substitution dynamical systems with a matrix that admits eigenvalues of mod-ulus 1. The functions γ we consider are the corresponding eigen-functions. In Theorem 1.1 we prove that the limit inferior of the ergodic sums (n, γ(x0) +... + γ(xn−1))n∈N is bounded for every point x in the phase space. In Theorem 1.2, we prove existence of limit distributions along certain exponential subsequences of times for substitutions of constant length. Under additional assumptions, we prove that ergodic integrals satisfy the Central Limit Theore