Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases
We study the diffusive dynamics of a system in a nonlinear velocity-dependent frictional environment within a continuous time random walk model. In this model, the motion is governed by a shear-thinning frictional force, $-\gamma_0v/[1+(v^2/v_{\mathrm{c}}^2)]^\mu$ ( $0\lt\mu\unicode{x2A7D}1$ ), wher...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | New Journal of Physics |
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| Online Access: | https://doi.org/10.1088/1367-2630/ad2b0d |
| _version_ | 1797290332437610496 |
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| author | Ming-Gen Li Jian Liu Li-Ming Fan Xian-Feng Yue Jing-Dong Bao Peng-Cheng Li |
| author_facet | Ming-Gen Li Jian Liu Li-Ming Fan Xian-Feng Yue Jing-Dong Bao Peng-Cheng Li |
| author_sort | Ming-Gen Li |
| collection | DOAJ |
| description | We study the diffusive dynamics of a system in a nonlinear velocity-dependent frictional environment within a continuous time random walk model. In this model, the motion is governed by a shear-thinning frictional force, $-\gamma_0v/[1+(v^2/v_{\mathrm{c}}^2)]^\mu$ ( $0\lt\mu\unicode{x2A7D}1$ ), where γ _0 represents the coefficient of static friction and µ is the scaling index. Through analytical and numerical results, we construct a diffusion phase diagram that encompasses different regimes upon variations in parameters γ _0 and µ : normal diffusion; superdiffusion; and hyperdiffusion. These transitions occur because the induced weaker friction enhances the diffusion. With a decrease in the scaling index, we find that the γ _0 -dependent exponent of diffusion converges towards the experimental findings for ultracold ^87 Rb atoms because the strong effective friction arises. The discrepancies between the fractional Lévy kinetics and the experimental findings may be potentially reconciled. We believe that these findings are helpful for analyzing experimental observations of cold atoms diffusing in optical lattices. |
| first_indexed | 2024-03-07T19:20:55Z |
| format | Article |
| id | doaj.art-561c4e4ed2ae468a8efb499b124513ff |
| institution | Directory Open Access Journal |
| issn | 1367-2630 |
| language | English |
| last_indexed | 2024-03-07T19:20:55Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | New Journal of Physics |
| spelling | doaj.art-561c4e4ed2ae468a8efb499b124513ff2024-02-29T11:10:12ZengIOP PublishingNew Journal of Physics1367-26302024-01-0126202305510.1088/1367-2630/ad2b0dDiffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gasesMing-Gen Li0https://orcid.org/0000-0002-4657-0960Jian Liu1https://orcid.org/0000-0002-8177-9225Li-Ming Fan2Xian-Feng Yue3Jing-Dong Bao4Peng-Cheng Li5Department of Physics, Shantou University , Shantou, Guangdong 515063, People’s Republic of ChinaDepartment of Physics, Beijing Technology and Business University , Beijing 100048, People’s Republic of ChinaCollege of Physical Science and Technology, Shenyang Normal University , Shenyang 110034, People’s Republic of ChinaDepartment of Physics, Shantou University , Shantou, Guangdong 515063, People’s Republic of ChinaDepartment of Physics, Beijing Normal University , Beijing 100875, People’s Republic of ChinaDepartment of Physics, Shantou University , Shantou, Guangdong 515063, People’s Republic of ChinaWe study the diffusive dynamics of a system in a nonlinear velocity-dependent frictional environment within a continuous time random walk model. In this model, the motion is governed by a shear-thinning frictional force, $-\gamma_0v/[1+(v^2/v_{\mathrm{c}}^2)]^\mu$ ( $0\lt\mu\unicode{x2A7D}1$ ), where γ _0 represents the coefficient of static friction and µ is the scaling index. Through analytical and numerical results, we construct a diffusion phase diagram that encompasses different regimes upon variations in parameters γ _0 and µ : normal diffusion; superdiffusion; and hyperdiffusion. These transitions occur because the induced weaker friction enhances the diffusion. With a decrease in the scaling index, we find that the γ _0 -dependent exponent of diffusion converges towards the experimental findings for ultracold ^87 Rb atoms because the strong effective friction arises. The discrepancies between the fractional Lévy kinetics and the experimental findings may be potentially reconciled. We believe that these findings are helpful for analyzing experimental observations of cold atoms diffusing in optical lattices.https://doi.org/10.1088/1367-2630/ad2b0ddiffusion transitionsanomalous viscoelastic dynamicsshear-thinning viscositycold atomscontinuous-time random walk |
| spellingShingle | Ming-Gen Li Jian Liu Li-Ming Fan Xian-Feng Yue Jing-Dong Bao Peng-Cheng Li Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases New Journal of Physics diffusion transitions anomalous viscoelastic dynamics shear-thinning viscosity cold atoms continuous-time random walk |
| title | Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases |
| title_full | Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases |
| title_fullStr | Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases |
| title_full_unstemmed | Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases |
| title_short | Diffusion transitions induced by shear-thinning viscosity: application to laser-cooled atomic gases |
| title_sort | diffusion transitions induced by shear thinning viscosity application to laser cooled atomic gases |
| topic | diffusion transitions anomalous viscoelastic dynamics shear-thinning viscosity cold atoms continuous-time random walk |
| url | https://doi.org/10.1088/1367-2630/ad2b0d |
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