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Pauli crystal melting in shaken optical traps
by Jiabing Xiang, Paolo Molignini, Miriam Büttner, Axel U. J. Lode
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Submission summary
| Authors (as registered SciPost users): | Paolo Molignini · Jiabing Xiang |
| Submission information | |
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| Preprint Link: | https://arxiv.org/abs/2204.10335v1 (pdf) |
| Code repository: | http://ultracold.org |
| Data repository: | https://gitlab.com/Jiabing/pauli-crystals |
| Date submitted: | 2022-04-27 09:13 |
| Submitted by: | Xiang, Jiabing |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
Pauli crystals are ordered geometric structures that emerge in trapped noninteracting fermionic systems due to their underlying Pauli repulsion. The deformation of Pauli crystals - often called melting - has been recently observed in experiments, but the mechanism that leads to it remains unclear. We address this question by studying the melting dynamics of N=6 fermions as a function of periodic driving and experimental imperfections in the trap (anisotropy and anharmonicity) by employing a combination of numerical simulations and Floquet theory. Surprisingly, we reveal that the melting of Pauli crystals is not simply a direct consequence of an increase in system energy, but is instead related to the trap geometry and the population of the Floquet modes. We show that the melting is absent in traps without imperfections and triggered only by a sufficiently large shaking amplitude in traps with imperfections.
Current status:
Reports on this Submission
Anonymous Report 1 on 2022-5-21 (Invited Report)
- Cite as: Anonymous, Report on arXiv:2204.10335v1, delivered 2022-05-21, doi: 10.21468/SciPost.Report.5046
Strengths
1. Timely studies of the roboustness of high order correlations with respect to external perturbations.
2. Quantifying a degree of angular correlations by introducing a concept of a recognition function.
3. Very detailed analysis of dynamics of the melting process by studying configuration density, recognition function, mean energy growth and excitation spectrum.
4. Different shapes of trapping potentials are discussed.
Weaknesses
1. Pauli crystals are a very peculiar example of high order spatial correlations. Applicability of the presented approach to interacting systems is only briefly mentioned in conclusions.
Report
The paper is very timely in a view of the recent experiments with ultracold atoms. The authors discuss spatial arrangement of atoms due to the Pauli exclusion principle. The main goal is to study a role of anharmonicity and anisotropy on the melting process due to periodic modulations of the trapping potential.
They use the MultiConfiguration Time-Dependent Hartree approach to generate dynamics of several indistinguishable particles. The authors show that melting is not a simple consequence of increasing of the system energy. They relate the melting process to the excitation spectrum of the system.
I find the paper valid and interesting. Not only studies of the dynamical process but also theoretical tools used deserve noticing.
In my opinion the recognition function introduced to measure "visibility" of Pauli crystals is a very interesting physical concept which, in addition to the configurations density, might be useful in analysis of high order correlations of various systems. This simple measure allows to quantify observed configurations. Reducing of the amount of information contained in the full many-body high-order correlation functions to the most important ones is necessary. The recognition function seems to be an interesting option.
Requested changes
1. I encourage authors to extend a comment on applicability of the presented formalism to studies of interating systems.
2. More detailed discussion of the recognition function might be of some interest - in particular a remark of how to define the recognition function for systems not possessing axial symmetry.