Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 19: Frustrated Magnets - Spin Liquids - Theory
TT 19.11: Vortrag
Montag, 12. März 2018, 17:45–18:00, H 3010
Looking at an antiferromagnet from a spin-liquid point of view — •Marc Daniel Schulz — TU Dortmund, Germany
The Z2 topological phase in the quantum dimer model on the Kagome-lattice is a candidate for the description of the low-energy physics of the anti-ferromagnetic Heisenberg model on the same lattice. We study the extend of the topological phase by interpolating between the exactly solvable parent Hamiltonian of the topological phase and an effective low-energy description of the Heisenberg model in terms of a quantum-dimer Hamiltonian. Therefore, we perform a perturbative treatment of the low-energy excitations in the topological phase including free and interacting quasi-particles. We find a phase transition driven by the condensation of bound states formed of topological excitations. The condensed phase corresponds to a valence bond solid and is characterized by a spontaneously broken rotational symmetry and a unit cell containing six sites.