3,087 research outputs found

    Energy density fluctuations in Early Universe

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    The primordial nucleosinthesys of the element can be influenced by the transitions of phase that take place after the Big Bang, such as the QCD transition. In order to study the effect of this phase transition, in this work we compute the time evolution of thermodynamical quantities of the early universe, focusing on temperature and energy density fluctuations, by solving the relevant equations of motion using as input the lattice QCD equation of state to describe the strongly interacting matter in the early universe plasma. We also study the effect of a primordial strong magnetic field by means of a phenomenological equation of state. Our results show that small inhomogeneities of strongly interacting matter in the early Universe are moderately damped during the crossover.Comment: 4 pages, 2 figures. Talk given at Sventh European Summer School on Experimental Nuclear Astrophysics, 15-27 September 2013, Santa Tecla (CT) - Ital

    Dielectric correction to the Chiral Magnetic Effect

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    We derive an electric current density jemj_{em} in the presence of a magnetic field BB and a chiral chemical potential μ5\mu_5. We show that jemj_{em} has not only the anomaly-induced term μ5B\propto \mu_5 B (i.e. Chiral Magnetic Effect) but also a non-anomalous correction which comes from interaction effects and expressed in terms of the susceptibility. We find the correction characteristically dependent on the number of quark flavors. The numerically estimated correction turns out to be a minor effect on heavy-ion collisions but can be tested by the lattice QCD simulation.Comment: 4 pages, 1 figur

    Critical Endpoint and Inverse Magnetic Catalysis for Finite Temperature and Density Quark Matter in a Magnetic Background

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    In this article we study chiral symmetry breaking for quark matter in a magnetic background, B\bm B, at finite temperature and quark chemical potential, μ\mu, making use of the Ginzburg-Landau effective action formalism. As a microscopic model to compute the effective action we use the renormalized quark-meson model. Our main goal is to study the evolution of the critical endpoint, CP{\cal CP}, as a function of the magnetic field strength, and investigate on the realization of inverse magnetic catalysis at finite chemical potential. We find that the phase transition at zero chemical potential is always of the second order; for small and intermediate values of B\bm B, CP{\cal CP} moves towards small μ\mu, while for larger B\bm B it moves towards moderately larger values of μ\mu. Our results are in agreement with the inverse magnetic catalysis scenario at finite chemical potential and not too large values of the magnetic field, while at larger B\bm B direct magnetic catalysis sets in.Comment: 6 pages, 2 figure

    Probing the QCD vacuum with an abelian chromomagnetic field: A study within an effective model

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    We study the response of the QCD vacuum to an external abelian chromomagnetic field in the framework of a non local Nambu-Jona Lasinio model with the Polyakov loop. We use the Lattice results on the deconfinement temperature of the pure gauge theory to compute the same quantity in the presence of dynamical quarks. We find a linear relationship between the deconfinement temperature with quarks and the squared root of the applied field strength, gHgH, in qualitative (and to some extent also quantitative) agreement with existing Lattice calculations. On the other hand, we find a discrepancy on the approximate chiral symmetry restoration: while Lattice results suggest the deconfinement and the chiral restoration remain linked even at non-zero value of gHgH, our results are consistent with a scenario in which the two transitions are separated as gHgH is increased.Comment: 14 pages, 7 figures, RevTeX4. Published version, with enlarged abstract and minor changes in the main tex

    Short-Term Neurodevelopmental Outcome in Term Neonates Treated with Phenobarbital versus Levetiracetam: A Single-Center Experience

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    BACKGROUND: Phenobarbital (PB) has been traditionally used as the first-line treatment for neonatal seizures. More recently, levetiracetam (LEV) has been increasingly used as a promising newer antiepileptic medication for treatment of seizures in neonates. OBJECTIVES: The aim of our study was to compare the effect of PB vs. LEV on short-term neurodevelopmental outcome in infants treated for neonatal seizures. METHOD: This randomized, one-blind prospective study was conducted on term neonates admitted to the Neonatal Intensive Care Unit of S. Bambino Hospital, University Hospital "Policlinico-Vittorio Emanuele," Catania, Italy, from February 2016 to February 2018. Thirty term neonates with seizures were randomized to receive PB or LEV; the Hammersmith Neonatal Neurological Examination (HNNE) was used at baseline (T0) and again one month after the initial treatment (T1). RESULTS: We found a significantly positive HNNE score for the developmental outcomes, specifically tone and posture, in neonates treated with LEV. There was no significant improvement in the HNNE score at T1 in the neonates treated with PB. CONCLUSION: This study suggests a positive effect of levetiracetam on tone and posture in term newborns treated for neonatal seizures. If future randomized-controlled studies also show better efficacy of LEV in the treatment of neonatal seizures, LEV might potentially be considered as the first-line anticonvulsant in this age grou
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