title: Perturbative series expansion for the gap of the evolution operator associated with the contact process.
abstract: The gap between the eigenvalues of the dominant and subdominant eigenvectors of the evolution operator associated with the contact process in one dimension is studied by perturbative series expansions in powers of the creation rate. The series expansion for the gap was computed with 49 coefficients. An analysis by Padé approximants allowed the determination of the critical creation rate and the time correlation critical exponent.
authors.affiliation: Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05315-970 São Paulo, São Paulo, Brazil.
authors.forename: Mário J
authors.initials: MJ
authors.lastname: de Oliveira