13,066 research outputs found
Fermi-Fermi Mixtures in the Strong Attraction Limit
The phase diagrams of low density Fermi-Fermi mixtures with equal or unequal
masses and equal or unequal populations are described at zero and finite
temperatures in the strong attraction limit. In this limit, the Fermi-Fermi
mixture can be described by a weakly interacting Bose-Fermi mixture, where the
bosons correspond to Feshbach molecules and the fermions correspond to excess
atoms. First, we discuss the three and four fermion scattering processes, and
use the exact boson-fermion and boson-boson scattering lengths to generate the
phase diagrams in terms of the underlying fermion-fermion scattering length. In
three dimensions, in addition to the normal and uniform superfluid phases, we
find two stable non-uniform states corresponding to (1) phase separation
between pure unpaired (excess) and pure paired fermions (molecular bosons); and
(2) phase separation between pure excess fermions and a mixture of excess
fermions and molecular bosons. Lastly, we also discuss the effects of the
trapping potential in the density profiles of condensed and non-condensed
molecular bosons, and excess fermions at zero and finite temperatures, and
discuss possible implications of our findings to experiments involving mixtures
of ultracold fermions.Comment: 12 Pages, 6 Figures and 1 Tabl
Two-species fermion mixtures with population imbalance
We analyze the phase diagram of uniform superfluidity for two-species fermion
mixtures from the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensation
(BEC) limit as a function of the scattering parameter and population imbalance.
We find at zero temperature that the phase diagram of population imbalance
versus scattering parameter is asymmetric for unequal masses, having a larger
stability region for uniform superfluidity when the lighter fermions are in
excess. In addition, we find topological quantum phase transitions associated
with the disappearance or appearance of momentum space regions of zero
quasiparticle energies. Lastly, near the critical temperature, we derive the
Ginzburg-Landau equation, and show that it describes a dilute mixture of
composite bosons and unpaired fermions in the BEC limit.Comment: 4 pages with 3 figures, accepted version to PR
Search for Associations Containing Young stars (SACY): Chemical tagging IC 2391 & the Argus association
We explore the possible connection between the open cluster IC 2391 and the
unbound Argus association identified by the SACY survey. In addition to common
kinematics and ages between these two systems, here we explore their chemical
abundance patterns to confirm if the two substructures shared a common origin.
We carry out a homogenous high-resolution elemental abundance study of eight
confirmed members of IC 2391 as well as six members of the Argus association
using UVES spectra. We derive spectroscopic stellar parameters and abundances
for Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni and Ba.
All stars in the open cluster and Argus association were found to share
similar abundances with the scatter well within the uncertainties, where [Fe/H]
= -0.04 +/-0.03 for cluster stars and [Fe/H] = -0.06 +/-0.05 for Argus stars.
Effects of over-ionisation/excitation were seen for stars cooler than roughly
5200K as previously noted in the literature. Also, enhanced Ba abundances of
around 0.6 dex were observed in both systems. The common ages, kinematics and
chemical abundances strongly support that the Argus association stars
originated from the open cluster IC 2391. Simple modeling of this system find
this dissolution to be consistent with two-body interactions.Comment: 17 pages, 7 figs, accepted for publication in MNRA
How Hertzian solitary waves interact with boundaries in a 1-D granular medium
We perform measurements, numerical simulations, and quantitative comparisons
with available theory on solitary wave propagation in a linear chain of beads
without static preconstrain. By designing a nonintrusive force sensor to
measure the impulse as it propagates along the chain, we study the solitary
wave reflection at a wall. We show that the main features of solitary wave
reflection depend on wall mechanical properties. Since previous studies on
solitary waves have been performed at walls without these considerations, our
experiment provides a more reliable tool to characterize solitary wave
propagation. We find, for the first time, precise quantitative agreements.Comment: Proof corrections, ReVTeX, 11 pages, 3 eps (Focus and related papers
on http://www.supmeca.fr/perso/jobs/
Modos de distribuição de composto orgânico em vinÃferas.
O presente trabalho teve por objetivo avaliar o efeito da distribuição do composto orgânico sobre a produção e a composição do mosto da uva de videiras Cabernet Sauvignon.bitstream/item/48507/1/Comunicado-Tecnico-104.pd
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