On the different Floquet Hamiltonians in a periodic-driven Bose-Josephson junction

Fuente: arXiv
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Autori principali: Lin, Xiaoshui, Rao, Zeyu, Gong, Ming
Natura: Preprint
Pubblicazione: 2023
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author Lin, Xiaoshui
Rao, Zeyu
Gong, Ming
author_facet Lin, Xiaoshui
Rao, Zeyu
Gong, Ming
contents The bosonic Josephson junction, one of the maximally simple models for periodic-driven many-body systems, has been intensively studied in the past two decades. Here, we revisit this problem with five different methods, all of which have solid theoretical reasoning. We find that to the order of $ω^{-2}$ ($ω$ is the modulating frequency), these approaches will yield slightly different Floquet Hamiltonians. In particular, the parameters in the Floquet Hamiltonians may be unchanged, increased, or decreased, depending on the approximations used. Especially, some of the methods generate new interactions, which still preserve the total number of particles; and the others do not. The validity of these five effective models is verified using dynamics of population imbalance and self-trapping phase transition. In all results, we find the method by first performing a unitary rotation to the Hamiltonian will have the highest accuracy. The difference between them will become significate when the modulating frequency is comparable with the driving amplitude. The results presented in this work indicate that the analysis of the Floquet Hamiltonian has some kind of subjectivity, which will become an important issue in future experiments with the increasing of precision. We demonstrate this physics using a Bose-Josephson junction, and it is to be hoped that the validity of these methods and their tiny differences put forward in this work can be verified in realistic experiments in future using quantum simulating platforms, including but not limited to ultracold atoms.
format Preprint
id arxiv_https___arxiv_org_abs_2312_16851
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle On the different Floquet Hamiltonians in a periodic-driven Bose-Josephson junction
Lin, Xiaoshui
Rao, Zeyu
Gong, Ming
Quantum Gases
Quantum Physics
The bosonic Josephson junction, one of the maximally simple models for periodic-driven many-body systems, has been intensively studied in the past two decades. Here, we revisit this problem with five different methods, all of which have solid theoretical reasoning. We find that to the order of $ω^{-2}$ ($ω$ is the modulating frequency), these approaches will yield slightly different Floquet Hamiltonians. In particular, the parameters in the Floquet Hamiltonians may be unchanged, increased, or decreased, depending on the approximations used. Especially, some of the methods generate new interactions, which still preserve the total number of particles; and the others do not. The validity of these five effective models is verified using dynamics of population imbalance and self-trapping phase transition. In all results, we find the method by first performing a unitary rotation to the Hamiltonian will have the highest accuracy. The difference between them will become significate when the modulating frequency is comparable with the driving amplitude. The results presented in this work indicate that the analysis of the Floquet Hamiltonian has some kind of subjectivity, which will become an important issue in future experiments with the increasing of precision. We demonstrate this physics using a Bose-Josephson junction, and it is to be hoped that the validity of these methods and their tiny differences put forward in this work can be verified in realistic experiments in future using quantum simulating platforms, including but not limited to ultracold atoms.
title On the different Floquet Hamiltonians in a periodic-driven Bose-Josephson junction
topic Quantum Gases
Quantum Physics
url https://arxiv.org/abs/2312.16851