SciPost Submission Page
Quantum rotor in a two-dimensional mesoscopic Bose gas
by Michał Suchorowski, Alina Badamshina, Mikhail Lemeshko, Michał Tomza, Artem G. Volosniev
Submission summary
| Authors (as registered SciPost users): | Michał Suchorowski · Artem Volosniev |
| Submission information | |
|---|---|
| Preprint Link: | https://arxiv.org/abs/2407.06046v1 (pdf) |
| Code repository: | https://gitlab.com/msuchorowski/egpe-solver |
| Date submitted: | 2024-07-09 15:42 |
| Submitted by: | Suchorowski, Michał |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We investigate a molecular quantum rotor in a two-dimensional Bose-Einstein condensate. The focus is on studying the angulon quasiparticle concept in the crossover from few- to many-body physics. To this end, we formulate the problem in real space and solve it with a mean-field approach in the frame co-rotating with the impurity. We show that the system starts to feature angulon characteristics when the size of the bosonic cloud is large enough to screen the rotor. More importantly, we demonstrate the departure from the angulon picture for large system sizes or large angular momenta where the properties of the system are determined by collective excitations of the Bose gas.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Current status:
Reports on this Submission
Strengths
1. clear problem statement
2. simple and powerful method explored
3. clear physical interpretation of the obtained results
4. plenty of new interesting results obtained
Weaknesses
I have some tiny remarks (please see the pdf file) but I would have not called them true weaknesses.
Report
I think the journal acceptance criteria are fully met.
Requested changes
1. The physical origin of the impurity-boson interaction is unclear. The manuscript suggests the rotor model for the impurity. Are bosons also rotors?
2. On p.~4 we read: ``The normalized function $\psi$ defines the probability of finding a boson at a given position in a molecular frame of reference. It does not depend explicitly on the angle $\varphi_I$...'', however, coordinates ${\bf r}_i$ explicitly suggest such dependence. I think this issue should be clarified in the revised manuscript.
3. What do the authors mean by the following sentence: ``Indeed, a strong deformation of the density of the Bose gas requires a number of phonons in momentum space for its description.''?
4. The breakdown of the angulon behavior at large angular momenta (see Fig.~6) is signaled as a deviation of the rotation energy from the quadratic law. However, at large $L$ the energy $\Delta E^{num}_L$ seems to support a linear dependence. Is it really linear, and is there some physical reasoning for it?
Recommendation
Publish (easily meets expectations and criteria for this Journal; among top 50%)