Quantum fluctuations in atomic Josephson junctions: the role of dimensionality

Year: 2024

Authors: Bardin A., Lorenzi F., Salasnich L.

Autors Affiliation: Univ Padua, Dipartimento Fis & Astron Galileo Galilei, Via Marzolo 8, I-35131 Padua, Italy; Ist Nazl Fis Nucl INFN, Sez Padova, Via Marzolo 8, I-35131 Padua, Italy; Univ Padua, Padua QTech Ctr, Via Gradenigo 6A, I-35131 Padua, Italy; Consiglio Nazl Ric CNR, Ist Nazl Ott INO, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy.

Abstract: We investigate the role of quantum fluctuations in the dynamics of a bosonic Josephson junction in D spatial dimensions, by using beyond-mean-field Gaussian corrections. We derive some key dynamical properties in a systematic way for D=3,2,1 . In particular, we compute the Josephson frequency in the regime of low population imbalance. We also obtain the critical strength of the macroscopic quantum self-trapping. Our results show that quantum corrections increase the Josephson frequency in spatial dimensions D = 2 and D = 3, but they decrease it in the D = 1 case. The critical strength of macroscopic quantum self-trapping is instead reduced by quantum fluctuations in D = 2 and D = 3 cases, while it is enhanced in the D = 1 configuration. We show that the difference between the cases of D = 2 and D = 3 on one side, and D = 1 on the other, can be related to the qualitatively different dependence of the interaction strength on the scattering length in the different dimensions.

Journal/Review: NEW JOURNAL OF PHYSICS

Volume: 26 (1)      Pages from: 13021-1  to: 13021-19

More Information: F L thanks Andrea Richaud for useful comments and suggestions. This work is partially supported by the BIRD grant ’Ultracold atoms in curved geometries’ of the University of Padova, by the ’IniziativaSpecifica Quantum’ of INFN, by the European Union-NextGenerationEU within the National Center for HPC, Big Data and Quantum Computing (Project No. CN00000013, CN1 Spoke 10: ’Quantum Computing’), by the EU Project PASQuanS 2 ’Programmable Atomic Large-Scale Quantum Simulation’, and the National Grant of the Italian Ministry of University and Research for the PRIN 2022 project ’Quantum Atomic Mixtures: Droplets, Topological Structures, and Vortices’.
KeyWords: beyond mean-field; quantum fluctuations; bosonic Josephson junction; Gaussian corrections
DOI: 10.1088/1367-2630/ad127b

Citations: 2
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