dorsal/arxiv
View SchemaBrownian motion of a rod threading through a ring with fixed ring-center
| Authors | Zhongqiang Xiong, Shigeyuki Komura, Masao Doi |
|---|---|
| Categories | |
| ArXiv ID | 2601.08130vv1 |
| URL | https://arxiv.org/abs/2601.08130 |
| License | http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
Abstract
We study the Brownian motion of a rigid rod threading through a small fixed ring while the ring can freely rotate. We derive the distribution function for the sliding displacement and the unit vector along the rod both at equilibrium and non-equilibrium. The equilibrium distribution is quadratic in the sliding displacement and is controlled by the moment of inertia (mass distribution). Applying the Onsager variational principle, we derive a Smoluchowski equation in which sliding and rotational diffusion are coupled. The mean square displacement (MSD) of sliding shows a metastable plateau in a certain time range before it approaches the final equilibrium value. The longest sliding relaxation time decreases as $\alpha^{-1/2}$ as the moment of inertia increases. The rotational relaxation time obtained from the orientational correlation function is longer than that of a rod with its center fixed but faster than a rod with one end fixed. These results may be useful in understanding the dynamics of polymers connected by sliding rings.
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"abstract": "We study the Brownian motion of a rigid rod threading through a small fixed ring while the ring can freely rotate. We derive the distribution function for the sliding displacement and the unit vector along the rod both at equilibrium and non-equilibrium. The equilibrium distribution is quadratic in the sliding displacement and is controlled by the moment of inertia (mass distribution). Applying the Onsager variational principle, we derive a Smoluchowski equation in which sliding and rotational diffusion are coupled. The mean square displacement (MSD) of sliding shows a metastable plateau in a certain time range before it approaches the final equilibrium value. The longest sliding relaxation time decreases as $\\alpha^{-1/2}$ as the moment of inertia increases. The rotational relaxation time obtained from the orientational correlation function is longer than that of a rod with its center fixed but faster than a rod with one end fixed. These results may be useful in understanding the dynamics of polymers connected by sliding rings.",
"arxiv_id": "2601.08130",
"authors": [
"Zhongqiang Xiong",
"Shigeyuki Komura",
"Masao Doi"
],
"categories": [
"cond-mat.soft"
],
"license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
"title": "Brownian motion of a rod threading through a ring with fixed ring-center",
"url": "https://arxiv.org/abs/2601.08130",
"version": "v1"
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