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Out of equilibrium many-body expansion dynamics of strongly interacting bosons
by Rhombik Roy, Barnali Chakrabarti, Arnaldo Gammal
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Submission summary
| Authors (as registered SciPost users): | Barnali Chakrabarti |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202306_00030v1 (pdf) |
| Date submitted: | 2023-06-23 09:05 |
| Submitted by: | Chakrabarti, Barnali |
| Submitted to: | SciPost Physics Core |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
We solve the Schr\"odinger equation from first principles to investigate the many-body effects in the expansion dynamics of one-dimensional repulsively interacting bosons released from a harmonic trap. We utilize the multiconfigurational time-dependent Hartree method for bosons (MCTDHB) to solve the many-body Schr\"odinger equation at high level of accuracy. The MCTDHB basis sets are explicitly time-dependent and optimised by variational principle. We probe the expansion dynamics by three key measures; time evolution of one-, two- and three-body densities. We observe when the mean-field theory results to unimodal expansion, the many-body calculation exhibits trimodal expansion dynamics. The many-body features how the initially fragmented bosons independently spreads out with time whereas the mean-field pictures the expansion of the whole cloud. We also present the three different time scale of dynamics of the inner core, outer core and the cloud as a whole. We analyze the key role played by the dynamical fragmentation during expansion. A Strong evidence of the many-body effects is presented in the dynamics of two- and three-body densities which exhibit correlation hole and pronounced delocalization effect.
Current status:
Reports on this Submission
Report #1 by Anonymous (Referee 2) on 2023-8-23 (Invited Report)
- Cite as: Anonymous, Report on arXiv:scipost_202306_00030v1, delivered 2023-08-23, doi: 10.21468/SciPost.Report.7703
Strengths
1- This is a very solid, useful numerical study.
Weaknesses
1- Several important early works are not cited.
2- The value of the coupling constant of choice is too close to the "hard-core" value to be meaningful. It is encouraging that the MCTDHB has been proven to be practically viable, but I would encourage the authors to look at the intermediate couplings, in their next paper.
Report
I am for publishing the paper, provided a few minor changes.
Requested changes
1- An early paper ["Breakdown of Time-Dependent Mean-Field Theory for a One-Dimensional Condensate of Impenetrable Bosons",
M. D. Girardeau and E. M. Wright, Phys. Rev. Lett. 84, 5239 (2000)] constitutes one of the first very explicit demonstrations of the breakdown of the mean-field approximation for strong interactions: it is not cited but it should be.
2- The foundational dynamical fermionization experiment [“Observation of dynamical fermionization”, Joshua M Wilson, Neel Malvania, Yuan Le, Yicheng Zhang, Marcos Rigol, David S Weiss, Science, 367, 1461 (2020)] needs to be cited.
3- The authors need to explain their choice for such a strong coupling ($\lambda = 25.$). I can imagine this was important to test the method, but this needs to be verbalized.
4- Fig. 4, if it is easy to accomplish, I would like to see a hard-core curve here as well.
Minor changes:
5- In "References", "Tonks-Girardeay", "Bose-Einstein", etc need to be capitalized.
6- Figs. 6-7 are missing the value of the coupling constant, in Captions.