30 research outputs found
Time-dependent Gross-Pitaevskii equation for composite bosons as the strong-coupling limit of the fermionic BCS-RPA approximation
The linear response to a space- and time-dependent external disturbance of a
system of dilute condensed composite bosons at zero temperature, as obtained
from the linearized version of the time-dependent Gross-Pitaevskii equation, is
shown to result also from the strong-coupling limit of the time-dependent BCS
(or broken-symmetry RPA) approximation for the constituent fermions subject to
the same external disturbance. In this way, it is possible to connect
excited-state properties of the bosonic and fermionic systems by placing the
Gross-Pitaevskii equation in perspective with the corresponding fermionic
approximationsComment: 4 pages, 1 figur
Shrinking of a condensed fermionic cloud in a trap approaching the BEC limit
We determine the zero-temperature density profile of a cloud of fermionic
atoms in a trap subject to a mutual attractive interaction, as the strength of
the interaction is progressively increased. We find a significant decrease of
the size of the atomic cloud as it evolves from the weak-coupling (BCS) regime
of overlapping Cooper pairs to the strong-coupling (Bose-Einstein) regime of
non-overlapping bound-fermion pairs. Most significantly, we find a pronounced
increase of the value of the density at the center of the trap (even by an
order of magnitude) when evolving between the two regimes. Our results are
based on a generalized Thomas-Fermi approximation for the superfluid state,
that covers continuously all coupling regimes.Comment: 5 pages, 3 postscript figure
The Sudbury Neutrino Observatory
The Sudbury Neutrino Observatory is a second generation water Cherenkov
detector designed to determine whether the currently observed solar neutrino
deficit is a result of neutrino oscillations. The detector is unique in its use
of D2O as a detection medium, permitting it to make a solar model-independent
test of the neutrino oscillation hypothesis by comparison of the charged- and
neutral-current interaction rates. In this paper the physical properties,
construction, and preliminary operation of the Sudbury Neutrino Observatory are
described. Data and predicted operating parameters are provided whenever
possible.Comment: 58 pages, 12 figures, submitted to Nucl. Inst. Meth. Uses elsart and
epsf style files. For additional information about SNO see
http://www.sno.phy.queensu.ca . This version has some new reference