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Pierfrancesco Buonsante |
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Politecnico di Torino |
Abstract
The
mean-field dynamics of an array of interacting Bose-Einstein condensates
(BECs) is in general non-integrable, and hence it is expected to give rise
to strongly irregular, possibly chaotic trajectories. The array consisting
of three BECs (trimer) is a paradigm for larger arrays, since it is at
the same time sufficiently complex to exhibit a non-integrable mean-field
dynamics and sufficiently simple to allow a
thorough
analytical study. These features, along with its forthcoming experimental
realization, promised by the most recent achievements in the field
of cold atom trapping, make the trimer worth studying.
A
description of the mean-field dynamics of the trimer for every choice of
the significant Hamiltonian parameters is obtained by means of a systematic
analysis of the configuration and stability character of its fixed points.
The remarkable operational value of the diagrams summarizing our analytical
results is widely confirmed by numerical simulations where slight changes
in the parameters give rise to macroscopic (i.e. experimentally accessible)
effects.
Furthermore,
some preliminary results put into evidence an interesting persistence of
mean-field features in the purely quantum description of the system. These
investigations are inspired by previous works concerning the symmetric
dimer and extend the results reported there to the asymmetric dimer and
to the trimer.
A
quantum scheme describing the (integrable) dimeric subregime of
the trimer dynamics is also proposed. The su(1,1) structure of the relevant
quantum Hamiltonian is brought into relation with the stability character
of the dimeric fixed points.