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Out of equilibrium many-body expansion dynamics of strongly interacting bosons

by Rhombik Roy, Barnali Chakrabarti, Arnaldo Gammal

This Submission thread is now published as

Submission summary

Authors (as registered SciPost users): Barnali Chakrabarti
Submission information
Preprint Link: scipost_202306_00030v2  (pdf)
Date accepted: 2023-09-25
Date submitted: 2023-09-12 10:42
Submitted by: Chakrabarti, Barnali
Submitted to: SciPost Physics Core
Ontological classification
Academic field: Physics
  • Atomic, Molecular and Optical Physics - Theory
  • Condensed Matter Physics - Theory
  • Condensed Matter Physics - Computational
Approaches: Theoretical, Computational


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.

Published as SciPost Phys. Core 6, 073 (2023)

Author comments upon resubmission

The Editor,

We would like to express our sincere gratitude to the Editor of SciPost Physics Core for their valuable suggestion to revise our manuscript and giving us the opportunity to resubmit it.

We are also deeply appreciative of the meticulous review by the Referee. In accordance with the referee's recommendations, we have diligently revised the manuscript. In this correspondence, we have taken into consideration all of the comments made and have made the necessary corrections accordingly.

After all substantial corrections, we firmly believe that the new physics presented in this article will be of significant interest to the readers of SciPost Physics Core. We earnestly request that you consider processing our manuscript for publication based on the aforementioned revisions.

Thanking you.
R. Roy, B. Chakrabarti, and A. Gammal

List of changes

The following improvements have been incorporated into our current work:

1. We have appropriately added the necessary citations throughout the manuscript.

2. A discussion on the rationale behind choosing strong interaction has been included in the revised manuscript (found in the last paragraph of page 4).

3. In response to the suggestion of incorporating hard-core bosons, we regret to inform you that we were unable to run the code for hard-core bosons. It is not clear to us which parameters of the hard-core should be chosen. Anyways, it goes beyond our present calculation, and convergence would be a major effort. Instead, we have included a discussion on the fermionic population, (in Figure 5 of new manuscript), and the discussion can be found on page 9.

4. We have revised the references and figure captions as per the recommendations of the referee. We made revisions to both Fig. 7 and Fig. 8, and we also improved the "Quantities of interest" section to enhance its clarity.

Submission & Refereeing History

Reports on this Submission

Anonymous Report 1 on 2023-9-19 (Invited Report)


I am satisfied with the changes made, the manuscript can be published as is.

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Anonymous on 2023-09-12  [id 3974]


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