Berlin 2005 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 11: Correlated Electrons - Spin Systems and Itinerant Magnets: Theory

TT 11.2: Vortrag

Samstag, 5. März 2005, 09:00–09:15, TU H2053

String Picture of a Frustrated Quantum Magnet and Dimer Model — •Ying Jiang and Thorsten Emig — Institut für Theoretische Physik, Universität zu Köln, Zülpicher Str. 77, 50937 Köln

We study the effect of quantum dynamics on geometrically frustrated magnets for a transverse field Ising model at finite temperatures. We develop a microscopic derivation of the Landau-Ginzburg-Wilson (LGW) action for this model and show that it can be interpreted as the free energy of a 3D elastic lattice of non-crossing strings. As a first application, we quantitatively predict the phase diagram and correlations, confirming excellently a key prediction of recent simulations about the existence of unusual phase transitions and an ordered phase. We discuss implications of our string picture for the understanding of the effect of quenched disorder in such quantum frustrated systems.