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DY: Dynamik und Statistische Physik

DY 12: Dynamical Phenomena

DY 12.5: Hauptvortrag

Montag, 8. März 2004, 12:30–13:00, H2

Local scale invariance in ageing phenomena — •Malte Henkel — Laboratoire de Physique des Matériaux, Université Henri Poincaré Nancy I, B.P. 239, F - 54506 Vandœuvre-lès-Nancy, France

The temporal behaviour of ageing systems is described by the two-time correlators C(t,s) and the response function R(t,s), where t is the observation time and s is the waiting time. The dynamical scaling in ageing systems leads to the scaling form R(t,s)=s^−1−a f(t/s). The extension of dynamical scaling to a local scale invariance, in close analogy to conformal invariance, is studied. In particular, if the dynamical exponent z=2, we show that through a Ward identity, Galilei invariance implies local scale invariance. This in turn leads to an explicit form of f(x), which is tested via extensive simulation in the ageing 2D/3D Glauber-Ising model. This provides the first evidence for Galilei invariance in an ageing system. In addition, local scale invariance allows to reliably extract the exponent a from integrated response functions (dynamical susceptibilities). [1] M. Henkel, Nucl. Phys. B641, 405 (2002). [2] M. Henkel, J. Unterberger, Nucl. Phys. B660, 407 (2003) [3] M. Henkel, M. Pleimling, Phys. Rev. E, cond-mat/0302482 [4] M. Henkel, M. Paessens, M. Pleimling, Europhys. Lett. 62, 664 (2003) and cond-mat/0310761.