Berlin 2012 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 11: Transport: Quantum Coherence and Quantum Information Systems 2 (jointly with MA and HL)
TT 11.9: Vortrag
Montag, 26. März 2012, 17:15–17:30, BH 243
Entanglement, Fluctuations, and Quantum Critical Points — •Stephan Rachel1, Nicolas Laflorencie2, H. Francis Song1, and Karyn Le Hur3,1 — 1Department of Physics, Yale University, New Haven, CT 06520, USA — 2Laboratoire de Physique Theorique, Universite de Toulouse, UPS, (IRSAMC), F-31062 Toulouse, France — 3Center for Theoretical Physics, Ecole Polytechnique, 91128 Palaiseau Cedex, France
We show that bipartite fluctuations F can be considered an entanglement measure. We further demonstrate that the concept of bipartite fluctuations F provides a very efficient tool to detect quantum phase transitions in strongly correlated systems. We investigate paradigmatic examples for both quantum spins and bosons in one and two dimensions. As compared to the von Neumann entanglement entropy, we observe that F allows to find quantum critical points with a much better accuracy in one dimension. We further demonstrate that F can be successfully applied to the detection of quantum criticality in higher dimensions with no prior knowledge of the universality class of the transition. Promising approaches to experimentally access fluctuations are discussed for quantum antiferromagnets and cold gases.