Tunneling dynamics of a few bosons in a double well

Abstract

We study few-boson tunneling in a one-dimensional double well. As we pass from weak interactions to the fermionization limit, the Rabi oscillations first give way to highly delayed pair tunneling (for medium coupling), whereas for very strong correlations multi-band Rabi oscillations emerge. All this is explained on the basis of the exact few-body spectrum and without recourse to the conventional two-mode approximation. Two-body correlations are found essential to the understanding of the different tunnel mechanisms. The investigation is complemented by discussing the effect of skewing the double well, which offers the possibility to access specific tunnel resonances.

Distinguishability, degeneracy, and correlations in three harmonically trapped bosons in one dimension

“…The first limit is the fermionization of two bosons [17]. The second one is a composite fermionized gas [34], the smallest mixture that one can consider for an imbalanced number of atoms in the two species. Finally, if both g A and g AB → ∞, analytical forms of the wave functions can be proposed as well [24,45,47].…”

“…The following wave function has been proposed to be a good Ansatz for the wave function [34,40] 2,bos…”

“…By playing with both the intra-and interspecies interactions one can explore different physical phenomena, like phase separation on small atom mixtures [29][30][31][32][33]. Other relevant phenomena are the presence of a composite fermionized gas [34][35][36], quantum magnetism [37][38][39], or a crossover between composite fermionization and phase separation [40,41]. Also, these small number bosonic mixtures allow for the study of dynamical phenomena, like the tunneling of one species through the barrier formed by the other species [42,43] or the dynamical emergence of orthogonality catastrophe [44].…”

Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons

“…(3) and the wave function has nodes only when two atoms of different species meet, as expected in the composite fermionization limit [8]. For strong correlations in the A component (g A → ∞), on the other hand, ansatz (3) gains additional nodes and the wave function vanishes whenever two atoms of species A-A or A-B meet.…”

“…In the first regime the interactions between the atoms of different species are strong, while the interactions between the atoms of the same species are weak. This is the so-called composite fermionization limit [8,9], which shows strong anticorrelations between unlike atoms, similar to the ones between like atoms in the standard TG gas [10]. Since the occupation number of the lowest natural orbital for each species, A and B, scales more rapidly than N A,B but more slowly than N A,B , neither of them is fully Bose * magarciamarch@ecm.ub.edu condensed.…”