573 research outputs found

    Generalized Ginzburg-Landau approach to inhomogeneous phases in nonlocal chiral quark models

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    We analyze the presence of inhomogeneous phases in the QCD phase diagram within the framework of nonlocal chiral quark models. We concentrate in particular in the positions of the tricritical (TCP) and Lifshitz (LP) points, which are studied in a general context using a generalized Ginzburg-Landau approach. We find that for all the phenomenologically acceptable model parametrizations considered the TCP is located at a higher temperature and a lower chemical potential in comparison with the LP. Consequently, these models seem to favor a scenario in which the onset of the first order transition between homogeneous phases is not covered by an inhomogeneous, energetically favored phase.Comment: 9 pages, 1 figure. V2: Two references added, figure modified, minor changes in the text introduced. Matches version to be published in Physics Letters

    Deconfinement and chiral restoration in nonlocal SU(3) chiral quark models

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    We study the features of nonlocal SU(3) chiral quark models with wave function renormalization. Model parameters are determined from meson phenomenology, considering different nonlocal form factor shapes. In this context we analyze the characteristics of the deconfinement and chiral restoration transitions at finite temperature, introducing the couplings of fermions to the Polyakov loop. We analyze the results obtained for various thermodynamical quantities considering different Polyakov loop potentials and nonlocal form factors, in comparison with data obtained from lattice QCD calculations.Comment: 25 pages, 5 figures. Discussion of results enlarged, figures modified, references added. Version to appear in Physical Review

    Inhomogeneous phases in nonlocal chiral quark models

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    The presence of inhomogeneous phases in the QCD phase diagram is analyzed within chiral quark models that include nonlocal interactions. We work at the mean field level, assuming that the spatial dependence of scalar and pseudo-scalar condensates is given by a dual chiral density wave. Phase diagrams for Gaussian nonlocal form factors are studied in detail and compared with those obtained within the Nambu-Jona-Lasinio model and quark-meson approaches.Comment: 14 pages, 3 figure

    The Role of the New Technologies in the Italian Primary School: Historical and Educational Outlines

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    Education is a process which helps the growth of the students. Thanks to it students can grow, develop and become adult and qualified persons in different fields of the humans ’ activity. Hence, the school educates only when it supports the students in getting and developing their own skills and when it helps them to get new attitudes towards themselves as well as the human, natural and artificial world. In this perspective, the school cannot continue to be a mere teaching-learning environment, just making frontal lessons, even if with the support of advanced multimedia technologies, but it should, indeed, focus the attention on the learning processes. This is the deepest change that the school needs. The possibilities offered by the computers in the educational field are many, especially as support in special didactics. In this sense, the access to multimedia and telematics has caused the activation of an autonomous process to build knowledge. The interpersonal exchanges mediated by the computer can break the isolation of a disabled person. The introduction of multimedia in school can then enhance both the teacher and the student to help the cooperative dimension of the teaching / learning process. The school has to open itself to new technologies and help the students to select the necessary information for the construction of th

    A thorough dynamic interpretation of residual dipolar couplings in ubiquitin.

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    dipolar couplings (rdcs), ubiquitin The presence of slow motions with large amplitudes, as detected by measurements based on residual dipola

    Charged pseudoscalar and vector meson masses under strong magnetic fields in an extended NJL model

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    The mass spectrum of π+\pi^+ and ρ+\rho^+ mesons in the presence of a static uniform magnetic field B⃗\vec B is studied within a two-flavor NJL-like model. We improve previous calculations taking into account the effect of Schwinger phases carried by quark propagators, and using an expansion of meson fields in terms of the solutions of the corresponding equations of motion for nonzero BB. It is shown that the meson polarization functions are diagonal in this basis. Our numerical results for the ρ+\rho^+ meson spectrum are found to disfavor the existence of a meson condensate induced by the magnetic field. In the case of the π+\pi^+ meson, π\pi - ρ\rho mixing effects are analyzed for the meson lowest energy state. The predictions of the model are compared with available lattice QCD results.Comment: 35 pages, 4 figures. arXiv admin note: text overlap with arXiv:2205.1592
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