Sinha Supurna, Samuel Joseph
Raman Research Institute, Bangalore, India 560 080.
Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Apr;85(4 Pt 1):041802. doi: 10.1103/PhysRevE.85.041802. Epub 2012 Apr 5.
We present an analytical study of the role of thermal fluctuations in shaping molecular elastic properties of semiflexible polymers. Our study interpolates between mechanics and statistical mechanics in a controlled way and shows how thermal fluctuations modify the elastic properties of biopolymers. We present a study of the minimum-energy configurations with explicit expressions for their energy and writhe and plots of the extension versus link for these configurations and a study of fluctuations around the local minima of energy and approximate analytical formulas for the free energy of stretched twisted polymers. The central result of our study is a closed-form expression for the leading thermal fluctuation correction to the free energy around the nonperturbative writhing family solution for the configuration of a biopolymer. From the derived formulas, the predictions of the wormlike chain model for molecular elasticity can be worked out for a comparison against numerical simulations and experiments.
我们对热涨落在塑造半柔性聚合物分子弹性性质中的作用进行了分析研究。我们的研究以可控方式在力学和统计力学之间进行插值，并展示了热涨落如何改变生物聚合物的弹性性质。我们给出了对具有明确能量和扭曲表达式的最小能量构型的研究，以及这些构型的伸长与链节关系图，还给出了围绕能量局部极小值的涨落研究以及拉伸扭曲聚合物自由能的近似解析公式。我们研究的核心结果是一个封闭形式的表达式，用于对生物聚合物构型的非微扰扭曲族解周围的自由能进行主导热涨落修正。从推导公式中，可以得出蠕虫状链模型对分子弹性的预测，以便与数值模拟和实验进行比较。
