Berlin 2008 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 19: Correlated Electrons: Quantum-Critical Phenomena
TT 19.16: Talk
Tuesday, February 26, 2008, 18:15–18:30, H 3010
Quantum critical scaling behavior of deconfined spinons — •Flavio Nogueira1, Steinar Kragset2, and Asle Sudbo2 — 1Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin — 2Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
We perform a renormalization group analysis of some important effective field theoretic models for deconfined spinons. We show that deconfined spinons are critical for an isotropic SU(N) Heisenberg antiferromagnet, if N is large enough. We argue that nonperturbatively this result should persist down to N=2 and provide further evidence for the so called deconfined quantum criticality scenario. Deconfined spinons are also shown to be critical for the case describing a transition between quantum spin nematic and dimerized phases. On the other hand, the deconfined quantum criticality scenario is shown to fail for a class of easy-plane models. For the cases where deconfined quantum criticality occurs, we calculate the critical exponent η for the decay of the two-spin correlation function to first-order in є=4−d.