Anisotropic long-range interaction investigated with cold atoms
In two dimensions, a system of self-gravitating particles collapses and forms a singularity in finite time below a critical temperature Tc. We investigate experimentally a quasi-two-dimensional cloud of cold neutral atoms in interaction with two pairs of perpendicular counterpropagating quasiresonan...
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| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | English |
| Published: |
2021
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/145771 |
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| Institution: | Nanyang Technological University |
| Language: | English |
| Summary: | In two dimensions, a system of self-gravitating particles collapses and forms a singularity in finite time below a critical temperature Tc. We investigate experimentally a quasi-two-dimensional cloud of cold neutral atoms in interaction with two pairs of perpendicular counterpropagating quasiresonant laser beams, in order to look for a signature of this ideal phase transition: indeed, the radiation pressure forces exerted by the laser beams can be viewed as an anisotropic, and nonpotential, generalization of two-dimensional self-gravity. We first show that our experiment operates in a parameter range which should be suitable to observe the collapse transition. However, the experiment unveils only a moderate compression instead of a phase transition between the two phases. A three-dimensional numerical simulation shows that both the finite small thickness of the cloud, which induces a competition between the effective gravity force and the repulsive force due to multiple scattering, and the atomic losses due to heating in the third dimension contribute to smearing the transition. |
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