Dresden 2017 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 50: Correlated Electrons: Frustrated Magnets - Low-Dimensional Systems

TT 50.5: Talk

Wednesday, March 22, 2017, 16:00–16:15, HSZ 304

Critical behavior of quantum magnets with long-range interactions in the thermodynamic limit — •Sebastian Fey and Kai P. Schmidt — Lehrstuhl für Theoretische Physik I, Staudtstraße 7, Universität Erlangen-Nürnberg, D-91058 Erlangen, Germany

Quasi-particle properties of quantum magnets with long-range interactions are investigated by high-order linked-cluster expansions in the thermodynamic limit. It is established that perturbative continuous unitary transformations on white graphs are a promising and flexible approach to treat long-range interactions in quantum many-body systems. We exemplify this scheme for the one-dimensional transverse-field Ising chain with long-range interactions. For this model the elementary quasi-particle gap is determined allowing to access the quantum-critical regime including critical exponents and multiplicative logarithmic corrections for the ferro- and antiferromagnetic case.