Quantum Gutzwiller approach for the two-component Bose-Hubbard model

Year: 2022

Authors: Colussi V.E.; Caleffi F.; Menotti C.; Recati A.

Autors Affiliation: INO-CNR BEC Center and Dipartimento di Fisica, Universita di Trento, Via Sommarive 14, 38123, Povo, 38123, Italy; International School for Advanced Studies (SISSA), Via Bonomea 265, Trieste, I-34136, Italy; Trento Institute for Fundamental Physics and Applications, INFN, Via Sommarive 14, Trento, Povo, 38123, Italy

Abstract: We study the effects of quantum fluctuations in the two-component Bose-Hubbard model generalizing to mixtures the quantum Gutzwiller approach introduced recently in [Phys. Rev. Research 2, 033276 (2020)]. As a basis for our study, we analyze the mean-field ground-state phase diagram and spectrum of elementary excitations, with particular emphasis on the quantum phase transitions of the model. Within the quantum critical regimes, we address both the superfluid transport properties and the linear response dynamics to density and spin probes of direct experimental relevance. Crucially, we find that quantum fluctuations have a dramatic effect on the drag between the superfluid species of the system, particularly in the vicinity of the paired and antipaired phases absent in the usual one-component Bose-Hubbard model. Additionally, we analyse the contributions of quantum corrections to the one-body coherence and density/spin fluctuations from the perspective of the collective modes of the system, providing results for the few-body correlations in all the regimes of the phase diagram.


Volume: 12 (3)      Pages from: 111-1  to: 111-53

More Information: This project has received financial support from Provincia Autonoma di Trento and the Italian MIUR through the PRIN2017 project CEnTraL (Protocol Number 20172H2SC4).
KeyWords: mott insulator; superfluid; atoms; metal; gas
DOI: 10.21468/SciPostPhys.12.3.111