| Description |
The tunneling dynamics of a few boson system in a double-well is
investigated from an ab-initio perspective using the numerically exact
Multi-Configuration Time-Dependent Hartree method.
We first study a system consisting of single species of bosons with a
spatially modulated interaction. The main emphasis is on the role of
inhomogeneity and its effect on the tunneling. The dynamics changes
from Rabi oscillations in the non-interacting case to a highly
suppressed tunneling for intermediate interaction strengths followed
by a reappearance of tunneling near the fermionization limit. With
extreme interaction inhomogeneity in the regime of strong correlations
we observe tunneling between the higher bands. A richer behavior is
found for systems with higher particle number. For systems with more
than two bosons, the inhomogeneity of the interaction can be tuned to
generate tunneling resonances. These observations are explained on the
basis of the few-body spectrum and stationary eigenstates. A tilted
double-well and its interplay with the interaction asymmetry is
discussed next.
We then explore tunneling dynamics of binary bosonic mixtures. The
focus is on the role of the inter- and intra-species interactions and
their interplay. The dynamics is studied for three initial
configurations: complete and partial population imbalance and a phase
separated state. Increasing the inter-species interaction leads to a
strong increase of the tunneling time period analogous to the quantum
self-trapping for condensates. The intra-species repulsion can
suppress or enhance the tunneling period depending on the strength of
the inter-species correlations as well as the initial
configuration. Completely correlated tunneling between the two species
and within the same species as well as mechanisms of species
separation and counterflow are revealed. These effects are explained
by studying the many-body energy spectra as well as the properties of
the contributing stationary states.
|