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arXiv 2401.09246cond-mat.stat-mechphysics.bio-phphysics.comp-ph
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解链过程的工作分布

Work Distribution for Unzipping Processes

P. Werner, A. K. Hartmann, S. N. Majumdar

AI总结:

本文提出DNA/RNA发夹解链的拉链模型,解析计算自由长度分布P(L),并由此推导准静态线性加力过程中功分布P(W)的大偏差尾部,与数值模拟高度吻合。

摘要:

本文引入一个简单的拉链模型,以简化方式表示例如折叠的DNA双螺旋或RNA中的发夹结构。双链发夹与温度为$T$的热浴接触,并受到外力$f$的作用,该外力与解链序列的自由长度$L$耦合。在非常大的链的热力学极限下,增加力会导致在临界力$f_c(T)$处发生拉合/解链的一级相变。我们解析地计算了热力学极限下自由长度的完整分布$P(L)$,作为温度$T$和力$f$的函数,并证明该分布在$f<f_c$、$f=f_c$和$f>f_c$三种情况下具有本质不同的定性行为。接下来,我们考虑准静态做功过程,其中力按照线性协议递增。已获得的$P(L)$使我们能够推导出长链在拉合相$f<f_c$中功分布$P(W)$的解析表达式。我们显式计算了功分布的大偏差尾部。我们将功分布的解析结果在支撑集的大范围内与数值模拟进行比较,概率小至$10^{-200}$,数值模拟通过应用复杂的大偏差算法完成。

英文摘要:

A simple zipper model is introduced, representing in a simplified way, e.g., the folded DNA double helix or hairpin structures in RNA. The double stranded hairpin is connected to a heat bath at temperature $T$ and subject to an external force $f$, which couples to the free length $L$ of the unzipped sequence. Increasing the force, leads to an zipping/unzipping first-order phase transition at a critical force $f_c(T)$ in the thermodynamic limit of a very large chain. We compute analytically, as a function of temperature $T$ and force $f$, the full distribution $P(L)$ of free lengths in the thermodynamic limit and show that it is qualitatively very different for $f<f_c$, $f=f_c$ and $f>f_c$. Next we consider quasistatic work processes where the force is incremented according to a linear protocol. Having obtained $P(L)$ already allows us to derive an analytical expression for the work distribution $P(W)$ in the zipped phase $f<f_c$ for a long chain. We compute the large-deviation tails of the work distribution explicitly. Our analytical result for the work distribution is compared over a large range of the support down to probabilities as small as $10^{-200}$ with numerical simulations, which were performed by applying sophisticated large-deviation algorithms.

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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