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arXiv 1201.3263cond-mat.stat-mechcond-mat.soft
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压力波动引起的非平衡畴形成

Nonequilibrium domain formation by pressure fluctuations

Marco G. Mazza, Martin Schoen

摘要:

热多粒子系统中的涨落反映了平衡和非平衡(NEQ)物理学中的基本动力学过程。在NEQ系统中,\cite{ritort}波动在从斑图形成\cite{hohenberg,vdbroeck}到分子马达\cite{schaller,kierfeld,narayan,prost}的各种情况下都是重要的。在这里,我们解决的问题,如果和如何波动可能被用来表征和控制斑图形成在NEQ纳米系统。我们报告的液晶系统的扁长分子(介晶)夹在平坦的墙壁,并暴露于随时间变化的外部场的计算机模拟。我们发现,一个可切换的近晶域形式足够高的频率。虽然压力和温度太低而不能诱导平衡近晶相,但NEQ稳态中的压力波动与平衡近晶相的压力波动特征相匹配。此外,{ \it壁面法向}压力波动引起{ \it切向}“波动-涡度”张量,该张量指定近晶层的破裂方向。我们的计算证明了一种新的方法,通过该方法可以在原则上制造具有高度分子有序性的纳米材料。

英文摘要:

Fluctuations in thermal many-particle systems reflect fundamental dynamical processes in both equilibrium and nonequilibrium (NEQ) physics. In NEQ systems \cite{ritort} fluctuations are important in a variety of contexts ranging from pattern formation \cite{hohenberg,vdbroeck} to molecular motors \cite{schaller,kierfeld,narayan,prost}. Here, we address the question if and how fluctuations may be employed to characterize and control pattern formation in NEQ nanoscopic systems. We report computer simulations of a liquid crystal system of prolate molecules (mesogens) sandwiched between flat walls, and exposed to a time-dependent external field. We find that a switchable smectic domain forms for sufficiently high frequency. Although pressure and temperature are too low to induce an equilibrium smectic phase, the fluctuations of the pressure in the NEQ steady state match the pressure fluctuations characteristic of the equilibrium smectic phase. Furthermore, the {\it wall-normal} pressure fluctuations give rise to a {\it tangential} "fluctuation-vorticity" tensor that specifies the symmetry-breaking direction of the smectic layers. Our calculations demonstrate a novel method through which nanomaterials with a high degree of molecular order may be manufactured in principle.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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