Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 109: Frustrated Magnets - (General) Theory

TT 109.6: Vortrag

Freitag, 16. März 2018, 10:45–11:00, H 3005

Quantum criticality of 2d transverse-field Ising models with long-range interactions — •Sebastian Fey, Sebastian C. Kapfer, and Kai P. Schmidt — Lehrstuhl für Theoretische Physik I, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Germany

Most investigations on strongly correlated quantum many-body systems tackle short-range interactions. Very little is known so far on quantum criticality in the presence of long-range interactions, since such models are very hard to treat microscopically. Nevertheless, important examples of long-range interactions exist in nature, e.g. dipolar interactions in spin ice or long-range forces between cold atoms in optical lattices. Here we develop linked-cluster expansions with the help of classical Monte Carlo simulations to investigate the quantum-critical properies of the transverse-field Ising model with long-range interactions on two-dimensional lattices. In the unfrustrated cases we find different kinds of universality classes corresponding to the nearest-neighbor model, mean-field theory, as well as continuously varying critical exponents. In the frustrated cases our results agree with the scenario that the quantum-critical properties are always given by the model with nearest-neighbor interactions.