211 research outputs found

    Tomographic entropy and cosmology

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    The probability representation of quantum mechanics including propagators and tomograms of quantum states of the universe and its application to quantum gravity and cosmology are reviewed. The minisuperspaces modeled by oscillator, free pointlike particle and repulsive oscillator are considered. The notion of tomographic entropy and its properties are used to find some inequalities for the tomographic probability determining the quantum state of the universe. The sense of the inequality as a lower bound for the entropy is clarified.Comment: 19 page

    Cosmological dynamics in tomographic probability representation

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    The probability representation for quantum states of the universe in which the states are described by a fair probability distribution instead of wave function (or density matrix) is developed to consider cosmological dynamics. The evolution of the universe state is described by standard positive transition probability (tomographic transition probability) instead of the complex transition probability amplitude (Feynman path integral) of the standard approach. The latter one is expressed in terms of the tomographic transition probability. Examples of minisuperspaces in the framework of the suggested approach are presented. Possibility of observational applications of the universe tomographs are discussed.Comment: 16 page

    Морозоустойчивость культиваров Acer platanoides L., перспективных для высадки в городских условиях

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    Визначено потенційну морозостійкість Acer platanoides L. і його культиварів в умовах Києва та проведено порівняльну оцінку отриманих показників. Установлено, що найвищий рівень стійкості до низьких температур характерний для рослин A. p. 'Golden Globe', A. p. 'Princeton Gold' і A. p. 'Globosum'; найменш стійкими є A. p. 'Cleveland' і A. p. 'Columnare'. Усі досліджені культивари за сумарним рівнем пошкодження різних частин пагона розташовано у послідовний ряд морозостійкості. За результатами досліджень, для використання у міських насадженнях запропоновано культивари із цінними декоративними властивостями та високим рівнем стійкості до низьких температур.Potential frost resistance of Acer platanoides L. and its cultivars in the conditions of Kyiv city was identified and a comparative assessment of derived indicators was conducted. It is established that such cultivars as A. p. 'Golden Globe', A. p. 'Princeton Gold' and A. p. 'Globosum' were characterized by the highest resistance to low temperatures whereas the cultivars A. p. 'Cleveland' and A. p. 'Columnare' had the least frost resistance. All investigated cultivars by the total level of damage to different parts of the shoots were placed in the gradual row of frost resistance. The cultivars with valuable decorative features and high resistance to low temperatures were suggested to be used in urban plantings according to the results of the research.Определена потенциальная морозоустойчивость Acer platanoides L. и его культиваров в условиях Киева и проведена сравнительная оценка полученных показателей. Установлено, что высоким уровнем устойчивости к низким температурам характеризуются растения A. p. 'Golden Globe', A. p. 'Princeton Gold' и A. p. 'Globosum'; наименее устойчивыми являются A. p. 'Cleveland' и A. p. 'Columnare'. Все исследованные культивары по суммарному уровню повреждения различных частей побега расположены в последовательный ряд морозоустойчивости. По результатам исследований для использования в городских насаждениях предложены культивары с ценными декоративными свойствами и высоким уровнем устойчивости к низким температурам

    Formation of submicron relief structures on the surface of sapphire substrates

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    An analysis of technologies that allow creating microrelief structures on the surface of sapphire substrates has been carried out. It is shown that the most effective method of forming relief structures with submicron dimensions is ion beam   etching through a protective mask formed by photolithography. The main problems in creating a microrelief on the surface of sapphire substrates are the removal of static electric charge in the process of ion beam  etching of the substrates, as well as obtaining a protective mask with windows of specified sizes, through which etching of the sapphire substrate is performed

    Tomographic Representation of Minisuperspace Quantum Cosmology and Noether Symmetries

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    The probability representation, in which cosmological quantum states are described by a standard positive probability distribution, is constructed for minisuperspace models selected by Noether symmetries. In such a case, the tomographic probability distribution provides the classical evolution for the models and can be considered an approach to select "observable" universes. Some specific examples, derived from Extended Theories of Gravity, are worked out. We discuss also how to connect tomograms, symmetries and cosmological parameters.Comment: 15 page

    Detection model based on representation of quantum particles by classical random fields: Born's rule and beyond

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    Recently a new attempt to go beyond quantum mechanics (QM) was presented in the form of so called prequantum classical statistical field theory (PCSFT). Its main experimental prediction is violation of Born's rule which provides only an approximative description of real probabilities. We expect that it will be possible to design numerous experiments demonstrating violation of Born's rule. Moreover, recently the first experimental evidence of violation was found in the triple slits interference experiment, see \cite{WWW}. Although this experimental test was motivated by another prequantum model, it can be definitely considered as at least preliminary confirmation of the main prediction of PCSFT. In our approach quantum particles are just symbolic representations of "prequantum random fields," e.g., "electron-field" or "neutron-field"; photon is associated with classical random electromagnetic field. Such prequantum fields fluctuate on time and space scales which are essentially finer than scales of QM, cf. `t Hooft's attempt to go beyond QM \cite{H1}--\cite{TH2}. In this paper we elaborate a detection model in the PCSFT-framework. In this model classical random fields (corresponding to "quantum particles") interact with detectors inducing probabilities which match with Born's rule only approximately. Thus QM arises from PCSFT as an approximative theory. New tests of violation of Born's rule are proposed.Comment: Relation with recent experiment on violation of Born's rule in the triple slit experiment is discussed; new experimental test which might confirm violation of Born's rule are presented (double stochsticity test and interference magnitude test); the problem of "double clicks" is discusse

    ϒ production in p–Pb collisions at √sNN=8.16 TeV

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    ϒ production in p–Pb interactions is studied at the centre-of-mass energy per nucleon–nucleon collision √sNN = 8.16 TeV with the ALICE detector at the CERN LHC. The measurement is performed reconstructing bottomonium resonances via their dimuon decay channel, in the centre-of-mass rapidity intervals 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96, down to zero transverse momentum. In this work, results on the ϒ(1S) production cross section as a function of rapidity and transverse momentum are presented. The corresponding nuclear modification factor shows a suppression of the ϒ(1S) yields with respect to pp collisions, both at forward and backward rapidity. This suppression is stronger in the low transverse momentum region and shows no significant dependence on the centrality of the interactions. Furthermore, the ϒ(2S) nuclear modification factor is evaluated, suggesting a suppression similar to that of the ϒ(1S). A first measurement of the ϒ(3S) has also been performed. Finally, results are compared with previous ALICE measurements in p–Pb collisions at √sNN = 5.02 TeV and with theoretical calculations.publishedVersio

    (Anti-)deuteron production in pp collisions at 1as=13TeV

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    The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s=13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (d Nch/ d \u3b7 3c 26) as measured in p\u2013Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p\u2013Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM)

    Multiplicity dependence of inclusive J/psi production at midrapidity in pp collisions at root s=13 TeV

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    Measurements of the inclusive J/psi yield as a function of charged-particle pseudorapidity density dN(ch)/d eta in pp collisions at root s = 13 TeV with ALICE at the LHC are reported. The J/psi meson yield is measured at midrapidity (vertical bar y vertical bar <0.9) in the dielectron channel, for events selected based on the charged-particle multiplicity at midrapidity (vertical bar eta vertical bar <1) and at forward rapidity (-3.7 <eta <-1.7 and 2.8 <eta <5.1); both observables are normalized to their corresponding averages in minimum bias events. The increase of the normalized J/psi yield with normalized dN(ch)/d eta is significantly stronger than linear and dependent on the transverse momentum. The data are compared to theoretical predictions, which describe the observed trends well, albeit not always quantitatively. (C) 2020 European Organization for Nuclear Research. Published by Elsevier B.V.Peer reviewe

    Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report on the first measurement of the triangular v3v_3, quadrangular v4v_4, and pentagonal v5v_5 charged particle flow in Pb-Pb collisions at 2.76 TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow v2v_2 and v3v_3 have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.Comment: 10 pages, 4 figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387
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