15 research outputs found
Doorway states and the Bose-Hubbard model
We introduce an efficient method to solve the Mott-Hubbard model. The
Schr\"{o}dinger equation is solved by the successive construction of doorway
states. The ground state wavefunction derived by this method contains all
relevant many-body correlations introduced by the hamiltonian, but the
dimensionality of the Hilbert space is greatly reduced. We apply the doorway
method to obtain the chemical potential, the on-site fluctuations and the
visibility of the interference pattern arising from atoms in a one-dimensional
periodic lattice. Excellent agreement with exact numerical calculations as well
as recent experimental observations is found.Comment: 4 figure
Transverse momentum spectra of charged particles in proton-proton collisions at GeV with ALICE at the LHC
The inclusive charged particle transverse momentum distribution is measured
in proton-proton collisions at GeV at the LHC using the ALICE
detector. The measurement is performed in the central pseudorapidity region
over the transverse momentum range GeV/.
The correlation between transverse momentum and particle multiplicity is also
studied. Results are presented for inelastic (INEL) and non-single-diffractive
(NSD) events. The average transverse momentum for is (stat.) (syst.) GeV/ and
\left_{\rm NSD}=0.489\pm0.001 (stat.) (syst.)
GeV/, respectively. The data exhibit a slightly larger than measurements in wider pseudorapidity intervals. The results are
compared to simulations with the Monte Carlo event generators PYTHIA and
PHOJET.Comment: 20 pages, 8 figures, 2 tables, published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/390
Production of pions, kaons and protons in pp collisions at GeV with ALICE at the LHC
The production of , , , , p, and pbar at mid-rapidity
has been measured in proton-proton collisions at GeV with the
ALICE detector. Particle identification is performed using the specific energy
loss in the inner tracking silicon detector and the time projection chamber. In
addition, time-of-flight information is used to identify hadrons at higher
momenta. Finally, the distinctive kink topology of the weak decay of charged
kaons is used for an alternative measurement of the kaon transverse momentum
() spectra. Since these various particle identification tools give
the best separation capabilities over different momentum ranges, the results
are combined to extract spectra from = 100 MeV/ to 2.5 GeV/.
The measured spectra are further compared with QCD-inspired models which yield
a poor description. The total yields and the mean are compared with
previous measurements, and the trends as a function of collision energy are
discussed.Comment: 24 pages, 18 captioned figures, 5 tables, published version, figures
at http://aliceinfo.cern.ch/ArtSubmission/node/388
Sympathetic cooling and growth of a Bose-Einstein condensate
We study two sets of rate equations for sympathetic cooling of harmonically trapped Bose gases. Calculations for mixtures of Na-Rb and Li-Cs show that both sets yield similar results for the cooling times. The equilibration rates are in fair agreement with each other and differ considerably from classical rates. The onset of Bose-Einstein condensation is rather sudden and nonexponential in time, and the growth of the condensate differs for the two different mixtures we studied
Influencia del proceso de curado y del contenido de carga sobre la Tg y el volumen libre en compuestos particulados de matriz epoxi
Propagação in vitro de Baptistonia pubes (Lindl.) Chiron & V.P. Castro (Oncidium pubes Lindl.) (Orchidaceae) Propagation in vitro of Baptistonia pubes (Lindl.) Chiron & V.P. Castro (Oncidium pubes Lindl. - Orchidaceae)
Baptistonia pubes é uma epífita que ocorre na Floresta Atlântica do Brasil, no Paraguai e norte da Argentina. É considerada espécie vulnerável e ameaçada de extinção. Nossos objetivos foram avaliar a eficácia da germinação de suas sementes e o crescimento em dois pHs utilizando-se dois meios de cultura: Murashige-Skoog (modificado - (MS)) e meio nutritivo à base de banana nanica acrescido de NPK 20-20-20 (Plant Prood®) (BAN) variando-se as concentrações de nutrientes e pH para a germinação e para o crescimento inicial das plântulas. As sementes germinaram em média 15 dias após a inoculação, em todas as condições. A porcentagem de germinação variou entre 2,6 a 11,6%, sendo que a maior porcentagem ocorreu no pH=5,2 BAN e a menor no pH=6,2 MS/2. O meio BAN foi mais eficiente na germinação. Os pHs, em cada meio, alteraram significativamente as médias das sementes germinadas. As plântulas cresceram mais no meio nutritivo à base de banana nanica no pH = 5,2.<br>Baptistonia pubes is an epiphyte that grows in Brazilian Atlantic Forest, in Paraguay and northern Argentina. It is considered vulnerable and threatened with extinction. Our aim was to verify seed germination efficiency and growth at two pHs, using two culture mediums: Murashige-Skoog (modified - (MS)) and banana pulp with added NPK 20-20-20 (Plant Prood®) (BAN), with varied nutrient and pH concentrations for germination and for growth. The seeds germinated on average 15 days after the inoculation, at all conditions. The percentage of germination varied between 2.6 and 11.6 %. The highest percentage was at pH=5.2 BAN and the lowest at pH=6.2 MS/2. The banana pulp was most efficient for germination. The pHs, in each environment, altered significantly the averages of the germinated seeds. Seedling growth showed better results in the banana medium, pH = 5.
Exact dynamics of two ultra-cold bosons confined in a one-dimensional double-well potential
Transverse momentum spectra of charged particles in proton-proton collisions at 1as=900 GeV with ALICE at the LHC
The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at s=900 GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region (|\u3b7|<0.8) over the transverse momentum range 0.15<10 GeV/c. The correlation between transverse momentum and particle multiplicity is also studied. Results are presented for inelastic (INEL) and non-single-diffractive (NSD) events. The average transverse momentum for |\u3b7|<0.8 is \u3008pT\u3009INEL=0.483\ub10.001 (stat.)\ub10.007 (syst.) GeV/c and \u3008pT\u3009NSD=0.489\ub10.001 (stat.)\ub10.007 (syst.) GeV/c, respectively. The data exhibit a slightly larger \u3008pT\u3009 than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET. \ua9 2010
ALICE Electromagnetic Calorimeter Technical Design Report
The ALICE Electromagnetic Calorimeter technical design is reported