10,441 research outputs found
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
Single observable concurrence measurement without simultaneous copies
We present a protocol that allows us to obtain the concurrence of any two
qubit pure state by performing a minimal and optimal tomography of one of the
subsystems through measuring a single observable of an ancillary four
dimensional qudit. An implementation for a system of trapped ions is also
proposed, which can be achieved with present day experimental techniques.Comment: 4 pages, 1 figur
Quality aspects of pepino dulce fruits in distinct ripening stages, packaging forms and storage conditions.
Acclimatization of Tapeinochilos ananassae plantlets in association with arbuscular mycorrhizal fungi.
The objective of this work was to assess the potential of three isolates of arbuscular mycorrhizal fungi to promote growth of micropropagated plantlets of Tapeinochilos ananassae during acclimatization. The experiment was carried out in greenhouse, in a completely randomized block design, with four inoculation treatments: non-inoculated control and plants inoculated with Glomus etunicatum, Acaulospora longula or Gigaspora albida, with ten replicates. After 90 days, the following parameters were evaluated: survival rate, height, leaf and tiller number, leaf area, fresh and dry biomass, contents of macro- and micronutrients in the root and shoot, glomerospore number, and mycorrhizal colonization. The survival percentage was 100%, except for plants inoculated with G. albida (80%). The isolate G. etunicatum is more suitable for plant development, since it improves survival, growth, dry matter production, nutritional status, and vigor of T. ananassae micropropagated plants
The exponent of the non-abelian tensor square and related constructions of -groups
Let be a finite -group. In this paper we obtain bounds for the
exponent of the non-abelian tensor square and of , which
is a certain extension of by . In particular, we
bound in terms of and when admits
some specific normal subgroup . We also establish bounds for in terms of and either the nilpotency class or the coclass of the
group , improving some existing bounds
High Levels of Chromosomal Differentiation in Euchroma gigantea L. 1735 (Coleoptera, Buprestidae)
Euchroma giganteawas karyotypically studied using conventional staining, C-banding, silver nitrate staining and ribosomal fluorescent in situ hybridization (rDNA FISH). Broad wide autosomal polymorphism and a complex sex determination system were found in this beetle. Karyotype complements ranging from 2n = 32, X1X2X3Y1Y2Y3 to 2n = 36,X1X2X3Y1Y2Y3 were detected in the sample analyzed. Punctiform suernumerary chromosomes were present in the different karyotypes. The karyotypic evolution of Brazilian E. giganteamay have taken two directions, reduction in the diploid number of 2n = 36 to 24 through centric fusions or 2n = 24 to 36 due to chromosomal fissions. In addition, pericentric inversions were also involved. The complex multiple sex mechanism of this species seems to be old and well established since it is found in specimens from different populations. Small pericentromeric blocks of constitutive heterochromatin were located on the autosomes and terminal blocks were also found on some small pairs. The sex chromosomes showed larger constitutive heterochromatin blocks. Silver nitrate staining during prophase I of meiosis showed labeling of the sex chromosome chain. However, the rDNA sites could only be precisely determined by FISH, which permitted the identification of these ribosomal sites on chromosomes X1 and X2 of this species
Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields
Assuming that the order parameter corresponds to an equal spin triplet
pairing symmetry state, we calculate the effect of phase fluctuations in
quasi-one-dimensional superconductors at high magnetic fields applied along the
y (b') axis. We show that phase fluctuations can destroy the theoretically
predicted triplet reentrant superconducting state, and that they are
responsible for melting the magnetic field induced Josephson vortex lattice
above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur
On the nature of Lithium-rich giant stars: constraints from Beryllium abundances
We have derived beryllium abundances for 7 Li-rich giant (A(Li) > 1.5) stars
and 10 other Li-normal giants, with the aim of investigating the origin of the
Lithium in the Li-rich giants. In particular, we test the predictions of the
engulfment scenario proposed by Siess & Livio (1999), where the engulfment of a
brown dwarf or one or more giant planets would lead to a simultaneous
enrichment of 7Li and 9Be. We show that regardless their nature, none of the
stars studied in this paper were found to have detectable beryllium. Using
simple dilution arguments we show that the engulfment of an external object as
the sole source of Li enrichment is ruled out by the Li and Be abundance data.
The present results favor the idea that Li has been produced in the interior of
the stars by a Cameron-Fowler process and brought up to the surface by an extra
mixing mechanism.Comment: Accepted in A&
F-wave versus P-wave Superconductivity in Organic Conductors
Current experimental results suggest that some organic quasi-one-dimensional
superconductors exhibit triplet pairing symmetry. Thus, we discuss several
potential triplet order parameters for the superconducting state of these
systems within the functional integral formulation. We compare weak spin-orbit
coupling , , and symmetries via several thermodynamic
quantities. For each symmetry, we analyse the temperature dependences of the
order parameter, condensation energy, specific heat, and superfluid density
tensor.Comment: 5 pages, 4 figure
Organogênese in vitro de videira.
O objetivo do presente trabalho foi avaliar o efeito da N6-benzilaminopurina (BAP) no processo de regeneração via organogênese in vitro,em sete cultivares de videira
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