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| Main Authors: | , , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2507.11756 |
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| _version_ | 1866908451572023296 |
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| author | Rusch, Regina Satalsari, Yasamin Mohebi Zuccolotto-Bernez, Angel B. Escobedo-Sanchez, Manuel A. Franosch, Thomas |
| author_facet | Rusch, Regina Satalsari, Yasamin Mohebi Zuccolotto-Bernez, Angel B. Escobedo-Sanchez, Manuel A. Franosch, Thomas |
| contents | We investigate the dynamics of individual colloidal particles in a one-dimensional periodic potential using the intermediate scattering function (ISF) as a key observable. We elaborate a theoretical framework and derive formally exact analytical expressions for the ISF. We introduce and analyze a generalized ISF with two wave vectors to capture correlations in a periodic potential beyond the standard ISF. Relying on Bloch's theorem for periodic systems and, by solving the Smoluchowski equation for an overdamped Brownian particle in a cosine potential, we evaluate the ISF by numerically solving for the eigenfunctions and eigenvalues of the expression. We apply time-dependent perturbation theory to expand the ISF and extract low-order moments, including the mean-square displacement, the time-dependent diffusivity, and the non-Gaussian parameter. Our analytical results are validated through Brownian-dynamics simulations and experiments on 2D colloidal systems exposed to a light-induced periodic potential generated by two interacting laser beams. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_11756 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Intermediate scattering function of colloids in a periodic laser field Rusch, Regina Satalsari, Yasamin Mohebi Zuccolotto-Bernez, Angel B. Escobedo-Sanchez, Manuel A. Franosch, Thomas Soft Condensed Matter We investigate the dynamics of individual colloidal particles in a one-dimensional periodic potential using the intermediate scattering function (ISF) as a key observable. We elaborate a theoretical framework and derive formally exact analytical expressions for the ISF. We introduce and analyze a generalized ISF with two wave vectors to capture correlations in a periodic potential beyond the standard ISF. Relying on Bloch's theorem for periodic systems and, by solving the Smoluchowski equation for an overdamped Brownian particle in a cosine potential, we evaluate the ISF by numerically solving for the eigenfunctions and eigenvalues of the expression. We apply time-dependent perturbation theory to expand the ISF and extract low-order moments, including the mean-square displacement, the time-dependent diffusivity, and the non-Gaussian parameter. Our analytical results are validated through Brownian-dynamics simulations and experiments on 2D colloidal systems exposed to a light-induced periodic potential generated by two interacting laser beams. |
| title | Intermediate scattering function of colloids in a periodic laser field |
| topic | Soft Condensed Matter |
| url | https://arxiv.org/abs/2507.11756 |