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DY: Fachverband Dynamik und Statistische Physik

DY 12: Poster I

DY 12.46: Poster

Dienstag, 24. März 2009, 14:30–16:30, P1A

Plateau formation in the twist parameter of the bond alternating AF S=1/2 Heisenberg spin chain — •Rainer Bischof and Janke Wolfhard — Institut für Theoretische Physik, Universität Leipzig, Germany

The twist (order) parameter was introduced in [1] to signal a quantum phase transition between different valence bond configurations in various 1D quantum spin systems. We present quantum Monte Carlo simulations combined with quantum reweighting methods. At non-zero temperature we find the formation of a plateau in the twist (order) parameter around the (zero temperature) quantum critical point. We investigate the possibility that this plateau is related to the quantum critical region that fans out from the quantum critical point.

[1] M. Nakamura, S. Todo: Phys. Rev. Lett. 89, 077204 (2002).