913 research outputs found
Empirical Traffic Data and Their Implications for Traffic Modeling
From single vehicle data a number of new empirical results about the temporal
evolution, correlation, and density-dependence of macroscopic traffic
quantities have been determined. These have relevant implications for traffic
modeling and allow to test existing traffic models.Comment: For related work see
http://www.theo2.physik.uni-stuttgart.de/helbing.htm
Dynamics of a Heisenberg spin chain in the quantum critical regime: NMR experiment versus effective field theory
A comprehensive comparison between the magnetic field- and
temperature-dependent low frequency spin dynamics in the antiferromagnetic
spin-1/2 Heisenberg chain (AFHC) system copper pyrazine dinitrate, probed via
the 13C-nuclear magnetic resonance (NMR) relaxation rate 1/T1, and the field
theoretical approach in the Luttinger liquid (LL) regime has been performed. We
have found a very good agreement between the experiment and theory in the
investigated temperature and field range. Our results demonstrate how strongly
the quantum critical point affects the spin dynamics of Heisenberg spin chain
compounds.Comment: 5 pages, 3 figure
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