Institut Charles Sadron, 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France.
Phys Rev Lett. 2010 Jul 16;105(3):037802. doi: 10.1103/PhysRevLett.105.037802. Epub 2010 Jul 15.
Dense self-avoiding polymer chains in strictly two dimensions are compact objects with fractal contours. Using scaling arguments and molecular dynamics simulations (with negligible momentum conservation) it is shown that correlated amoebalike fluctuations of the (sub)chain contours dominate the relaxation dynamics on all scales. The incompressibility of the melt and the compactness of (sub)chains impose a scale-free constraint on the contour fluctuations. This leads to strong long range spatiotemporal correlations of the displacement field as shown, e.g., by the (negative) algebraic decay of the center-of-mass velocity correlation function C(t)∼-1/t(6/5) with time t.
在严格的二维空间中，密集的自回避聚合物链是具有分形轮廓的紧致物体。使用标度分析和分子动力学模拟（忽略动量守恒），表明（亚）链轮廓的相关变形虫状涨落主导了所有尺度上的弛豫动力学。熔体的不可压缩性和（亚）链的紧致性对轮廓涨落施加了无标度约束。这导致位移场的强远距离时空相关，例如，由质心速度相关函数 C(t)∼-1/t(6/5)随时间 t 的负幂次衰减所示。
