Generalized persistence exponents: an exactly soluble model
  It was recently realized that the persistence exponent appearing in the dynamics of nonequilibrium systems is a special member of a continuously varying family of exponents, describing generalized persistence properties. We propose and solve a simplified model of coarsening, where time intervals between spin flips are independent, and distributed according to a L\'evy law. Both the limit distribution of the mean magnetization and the generalized persistence exponents are obtained exactly. 
A. Baldassarri, J.P. Bouchaud, I. Dornic, and C. Godr\`eche