title: Two-loop functional renormalization for elastic manifolds pinned by disorder in N dimensions.
abstract: We study elastic manifolds in an N -dimensional random potential using a functional renormalization group. We extend to N>1 our previous construction of a field theory renormalizable to two loops. For isotropic disorder with O (N) symmetry we obtain the fixed point and roughness exponent to next order in epsilon=4-d , where d is the internal dimension of the manifold. Extrapolation to the directed polymer limit d=1 allows some handle on the strong coupling phase of the equivalent N -dimensional Kardar-Parisi-Zhang growth equation, and eventually suggests an upper critical dimension d(u) approximately 2.5.
authors.affiliation: CNRS-Laboratoire de Physique Théorique de l'Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Le Doussal
authors.forename: Kay Jörg
authors.initials: KJ
authors.lastname: Wiese