Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 34: Postersession Matter at Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-Cold Atoms
TT 34.1: Poster
Mittwoch, 25. März 2009, 14:00–18:00, P1A
Phase Diagram of a Bosonic Model on a Square Lattice with Competing Interactions — •Ansgar Kalz, Andreas Honecker, Sebastian Fuchs, and Thomas Pruschke — Institut für Theoretische Physik, Georg-August-Universität Göttingen
The analysis of frustrated spin systems reveals a variety of interesting phenomena as for example quantum criticality and ordering processes in exotic phases. The antiferromagnetic spin-1/2-Heisenberg model with nearest and next nearest neighbour interaction J1 and J2 shows a strong frustration near the critical point J2 ≈ J1/2. The simulation of this frustrated spin system via Quantum Monte Carlo methods is limited by the sign problem. Therefore we simulated a closely related bosonic model which can be applied to cold atoms in optical lattices. We present phase diagrams for the classical Ising limit and the quantum case at finite and zero temperature.