2,222 research outputs found
Triplon mean-field analysis of an antiferromagnet with degenerate Shastry-Sutherland ground states
We look into the quantum phase diagram of a spin-
antiferromagnet on the square lattice with degenerate Shastry-Sutherland ground
states, for which only a schematic phase diagram is known so far. Many exotic
phases were proposed in the schematic phase diagram by the use of exact
diagonalization on very small system sizes. In our present work, an important
extension of this antiferromagnet is introduced and investigated in the
thermodynamic limit using triplon mean-field theory. Remarkably, this
antiferromagnet shows a stable plaquette spin-gapped phase like the original
Shastry-Sutherland antiferromagnet, although both of these antiferromagnets
differ in the Hamiltonian construction and ground state degeneracy. We propose
a sublattice columnar dimer phase which is stabilized by the second and third
neighbor antiferromagnetic Heisenberg exchange interactions. There are also
some commensurate and incommensurate magnetically ordered phases, and other
spin-gapped phases which find their places in the quantum phase diagram.
Mean-field results suggest that there is always a level-crossing phase
transition between two spin gapped phases, whereas in other situations, either
a level-crossing or a continuous phase transition happens
Pemanfaatan Fermentasi Daun Singkong (Manihot Utilisima Pohl.) Dalam Pakan Buatan Terhadap Pertumbuhan Dan Kelulushidupan Benih Ikan Gurami (Osphronemus Gouramy Lac.)
Penelitian ini dilaksanakan pada 1 April-26 Mei 2015. Tujuan dari penelitian ini untuk mengetahui jumlah tepung daun singkong yang terfermentasi di dalam pakan yang berpengaruh terhadap pertumbuhan, efisiensi pakan, kecernaan pakan serta retensi protein pada ikan gurami (Osphronemus gouramy Lac.). Penelitian ini menggunakan metode Rancangan Acak Lengkap (RAL) dengan satu faktor, 5 taraf perlakuan dan 3 ulangan. Perlakuan dengan subtitusi tepung kedelai : tepung daun singkong terfermentasi dimana kontrol (100:0%), P1 (95:5%), P2 (90:10%), P3(85:15%), dan P4 (80:20%). Kadar protein pakan 30%. Hasil penelitian menunjukkan bahwa perlakuan tertinggi terdapat pada P2(90:10%) dengan kecernaan pakan 61,09%, tingkat efisiensi pakan 23,19%, retensi protein 22,82% dan laju pertumbuhan spesifik 2,24% per hari
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
Multi-particle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Measurements of multi-particle azimuthal correlations (cumulants) for charged
particles in p-Pb and Pb-Pb collisions are presented. They help address the
question of whether there is evidence for global, flow-like, azimuthal
correlations in the p-Pb system. Comparisons are made to measurements from the
larger Pb-Pb system, where such evidence is established. In particular, the
second harmonic two-particle cumulants are found to decrease with multiplicity,
characteristic of a dominance of few-particle correlations in p-Pb collisions.
However, when a gap is placed to suppress such correlations,
the two-particle cumulants begin to rise at high-multiplicity, indicating the
presence of global azimuthal correlations. The Pb-Pb values are higher than the
p-Pb values at similar multiplicities. In both systems, the second harmonic
four-particle cumulants exhibit a transition from positive to negative values
when the multiplicity increases. The negative values allow for a measurement of
to be made, which is found to be higher in Pb-Pb collisions at
similar multiplicities. The second harmonic six-particle cumulants are also
found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find
which is indicative of a Bessel-Gaussian
function for the distribution. For very high-multiplicity Pb-Pb
collisions, we observe that the four- and six-particle cumulants become
consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and
Pb-Pb are measured. These are found to be similar for overlapping
multiplicities, when a gap is placed.Comment: 25 pages, 11 captioned figures, 3 tables, authors from page 20,
published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/87
A note on comonotonicity and positivity of the control components of decoupled quadratic FBSDE
In this small note we are concerned with the solution of Forward-Backward
Stochastic Differential Equations (FBSDE) with drivers that grow quadratically
in the control component (quadratic growth FBSDE or qgFBSDE). The main theorem
is a comparison result that allows comparing componentwise the signs of the
control processes of two different qgFBSDE. As a byproduct one obtains
conditions that allow establishing the positivity of the control process.Comment: accepted for publicatio
Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at , 2.76 and 7 TeV
Measurements of the sphericity of primary charged particles in minimum bias
proton--proton collisions at , 2.76 and 7 TeV with the ALICE
detector at the LHC are presented. The observable is linearized to be collinear
safe and is measured in the plane perpendicular to the beam direction using
primary charged tracks with GeV/c in . The
mean sphericity as a function of the charged particle multiplicity at
mid-rapidity () is reported for events with different
scales ("soft" and "hard") defined by the transverse momentum of the leading
particle. In addition, the mean charged particle transverse momentum versus
multiplicity is presented for the different event classes, and the sphericity
distributions in bins of multiplicity are presented. The data are compared with
calculations of standard Monte Carlo event generators. The transverse
sphericity is found to grow with multiplicity at all collision energies, with a
steeper rise at low , whereas the event generators show the
opposite tendency. The combined study of the sphericity and the mean with multiplicity indicates that most of the tested event generators
produce events with higher multiplicity by generating more back-to-back jets
resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with
tune PERUGIA-2011 exhibits a noticeable improvement in describing the data,
compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16,
published version, figures from
http://aliceinfo.cern.ch/ArtSubmission/node/308
Measurements of 181Ta(n,2n)180Ta reaction cross-section at the neutron energy of 14.78 MeV
The cross-section of the 181Ta(n,2n)180Ta reaction has been measured with respect to the 197Au(n,2n)196Au monitor reaction at the incident neutron energy of 14.78± 0.20 MeV, using neutron activation analysis and off-line γ-ray spectrometric technique. The present measurement has been done at the energy where discrepant measured results are available in the EXFOR data library. The result has been compared with evaluated data libraries JEFF-3.3 and ENDF/B-VII.1. The present result has also been supported by theoretical predictions of nuclear model code TALYS1.8 and TALYS-1.9. The uncertainty and the correlations among the measured cross-section has been studied using co-variance analysis
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