We present here computational work on the center-of-mass displacements in thin polymer films of finite width without topological constraints and without momentum conservation obtained using a well-known lattice Monte Carlo algorithm with chain lengths ranging up to N = 8192. Computing directly the center-of-mass displacement correlation function CN(t) allows to make manifest the existence of scale-free colored forces acting on a reference chain. As suggested by the scaling arguments put forward in a recent work on three-dimensional melts, we obtain a negative algebraic decay CN(t) ∼ −1/(N t) for times t ≪ TN with TN being the chain relaxation time. This implies a logarithmic correction to the related center-of-mass mean square-displacement hN(t) as has been checked directly.
Note: Scale-free center-of-mass displacement correlations in polymer films without topological constraints and momentum conservation
J. P. Wittmer, N. Schulmann, P. Polińska, J. Baschnagel; Note: Scale-free center-of-mass displacement correlations in polymer films without topological constraints and momentum conservation. J. Chem. Phys. 14 November 2011; 135 (18): 186101. https://doi.org/10.1063/1.3662132
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