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TT: Fachverband Tiefe Temperaturen
TT 2: Symposium: High Magnetic Field Phenomena in Low Dimensional Magnets
TT 2.5: Hauptvortrag
Montag, 25. Februar 2008, 11:30–12:00, H 0104
Dimensional Reduction at a Quantum Critical Point — •Cristian Batista — Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
Competition between ground states near a quantum critical point is expected to lead to unconventional behavior in low dimensional systems. New phases of matter have been predicted, and explanations proposed for unsolved problems including non-Fermi liquid behavior and high temperature superconductivity using two-dimensional (2d) theories. In this talk, I will present a theory that describes the Bose-Einstein condensate (BEC) quantum critical point (QCP) in layered systems with a frustrated inter-layer coupling. I will demonstrate that the main effect of this geometric frustration is to reduce the dimensionality of the QCP (its critical exponents are the ones expected for a 2d system). In addition, I will present the first experimental evidence of dimensional reduction at a QCP observed in the Mott insulator BaCuSi2O6 (Han Purple).