Center-of-mass motion as a sensitive convergence test for variational multimode quantum dynamics

Cosme, J.G.; Weiss, C.; Brand, J.

doi:10.1103/physreva.94.043603

Center-of-mass motion as a sensitive convergence test for variational multimode quantum dynamics

Cosme, J.G.; Weiss, C.; Brand, J.

Authors

J.G. Cosme

C. Weiss

J. Brand

Abstract

Multimode expansions in computational quantum dynamics promise convergence toward exact results upon increasing the number of modes. Convergence is difficult to ascertain in practice due to the unfavorable scaling of required resources for many-particle problems and therefore a simplified criterion based on a threshold value for the least occupied mode function is often used. Here we show how the separable quantum motion of the center of mass can be used to sensitively detect unconverged numerical multiparticle dynamics in harmonic potentials. Based on an experimentally relevant example of attractively interacting bosons in one dimension, we demonstrate that the simplified convergence criterion fails to assure qualitatively correct results. Furthermore, the numerical evidence for the creation of two-hump fragmented bright soliton-like states presented by A. I. Streltsov et al. [Phys. Rev. Lett. 100, 130401 (2008)] is shown to be inconsistent with exact results. Implications for understanding dynamical fragmentation in attractive boson systems are briefly discussed.

Citation

Cosme, J., Weiss, C., & Brand, J. (2016). Center-of-mass motion as a sensitive convergence test for variational multimode quantum dynamics. Physical Review A, 94(4), Article 043603. https://doi.org/10.1103/physreva.94.043603

Journal Article Type	Article
Acceptance Date	Oct 3, 2016
Online Publication Date	Oct 3, 2016
Publication Date	Oct 3, 2016
Deposit Date	Oct 7, 2016
Publicly Available Date	Oct 7, 2016
Journal	Physical Review A
Print ISSN	2469-9926
Electronic ISSN	2469-9934
Publisher	American Physical Society
Peer Reviewed	Peer Reviewed
Volume	94
Issue	4
Article Number	043603
DOI	https://doi.org/10.1103/physreva.94.043603

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