Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 79: Correlated Electrons - Poster Session
TT 79.39: Poster
Mittwoch, 2. April 2014, 15:00–19:00, P2
1/d expansion for coupled dimer magnets — •Darshan G. Joshi1, Kris Coester2, Kai P. Schmidt2, and Matthias Vojta1 — 1Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany — 2Theoretische Physik, Technische Universität Dortmund, Otto-Hahn-Str. 4, 44221 Dortmund, Germany
Using bond operators we develop a systematic expansion in 1/d, where d is spatial dimension, for coupled-dimer Heisenberg magnets. We apply this technique to a model of dimers on a hypercubic lattice, a generalization of the square-lattice bilayer Heisenberg model to arbitrary d. The method covers both the quantum paramagnetic and antiferromagnetic phases including the quantum critical point. Physical observables such as the phase boundary, mode dispersions and ground-state energy are shown to have a systematic expansion in powers of 1/d and are calculated to next-to-leading order. In the paramagnetic phase, an expansion in ratio of inter-dimer and intra-dimer coupling for arbitrary d is shown to be consistent with the results of the 1/d expansion.