title: Roton Minimum as a Fingerprint of Magnon-Higgs Scattering in Ordered Quantum Antiferromagnets.
abstract: A quantitative description of magnons in long-range ordered quantum antiferromagnets is presented which is consistent from low to high energies. It is illustrated for the generic S=1/2 Heisenberg model on the square lattice. The approach is based on a continuous similarity transformation in momentum space using the scaling dimension as the truncation criterion. Evidence is found for significant magnon-magnon attraction inducing a Higgs resonance. The high-energy roton minimum in the magnon dispersion appears to be induced by strong magnon-Higgs scattering.
authors.affiliation: Lehrstuhl für Theoretische Physik 1, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Powalski
authors.affiliation: Lehrstuhl für Theoretische Physik 1, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: G S
authors.initials: GS
authors.lastname: Uhrig
authors.affiliation: Lehrstuhl für Theoretische Physik 1, Technische Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: K P
authors.initials: KP
authors.lastname: Schmidt