title: S matrix from matrix product states.
abstract: We use the matrix product state formalism to construct stationary scattering states of elementary excitations in generic one-dimensional quantum lattice systems. Our method is applied to the spin-1 Heisenberg antiferromagnet, for which we calculate the full magnon-magnon S matrix for arbitrary momenta and spin, the two-particle contribution to the spectral function, and higher order corrections to the magnetization curve. As our method provides an accurate microscopic representation of the interaction between elementary excitations, we envisage the description of low-energy dynamics of one-dimensional spin chains in terms of these particlelike excitations.
authors.affiliation: Department of Physics and Astronomy, Ghent University, Krijgslaan 281-S9, B-9000 Gent, Belgium.
authors.forename: Laurens
authors.initials: L
authors.lastname: Vanderstraeten
authors.affiliation: Department of Physics and Astronomy, Ghent University, Krijgslaan 281-S9, B-9000 Gent, Belgium.
authors.forename: Jutho
authors.initials: J
authors.lastname: Haegeman
authors.affiliation: Institute of Theoretical Physics, Leibniz Universität Hannover, Appelstrasse 2, D-30167 Hannover, Germany.
authors.forename: Tobias J
authors.initials: TJ
authors.lastname: Osborne
authors.affiliation: Department of Physics and Astronomy, Ghent University, Krijgslaan 281-S9, B-9000 Gent, Belgium and Vienna Center for Quantum Science, Universität Wien, Boltzmanngasse 5, A-1090 Wien, Austria.
authors.forename: Frank
authors.initials: F
authors.lastname: Verstraete