1,231 research outputs found
Basic-deformed quantum mechanics
Starting on the basis of -symmetric oscillator algebra and on the
associate -calculus properties, we study a deformed quantum mechanics
defined in the framework of the basic square-integrable wave functions space.
In this context, we introduce a deformed Schroedinger equation, which satisfies
the main quantum mechanics assumptions and admits, in the free case, plane wave
functions that can be expressed in terms of the q-deformed exponential,
originally introduced in the framework of the basic-hypergeometric functions.Comment: 10 page
Hot and dense hadronic matter in an effective mean field approach
We investigate the equation of state of hadronic matter at finite values of
baryon density and temperature reachable in high energy heavy ion collisions.
The analysis is performed by requiring the Gibbs conditions on the global
conservation of baryon number, electric charge fraction and zero net
strangeness. We consider an effective relativistic mean-field model with the
inclusion of Delta-isobars, hyperons and lightest pseudoscalar and vector
mesons degrees of freedom. In this context, we study the influence of the
Delta-isobars degrees of freedom in the hadronic equation of state and, in
connection, the behavior of different particle-antiparticle ratios and
strangeness production.Comment: 15 pages, to be published in Phys. Rev. C
Nonextensive statistical effects on nuclear astrophysics and many-body problems
Density and temperature conditions in many stellar core (like the solar core)
imply the presence of nonideal plasma effects with memory and long-range
interactions between particles. This aspect suggests the possibility that the
stellar core could not be in a global thermodynamical equilibrium but satisfies
the conditions of a metastable state with a stationary (nonextensive) power law
distribution function among ions. The order of magnitude of the deviation from
the standard Maxwell-Boltzmann distribution can be derived microscopically by
considering the presence of random electrical microfields in the stellar
plasma. We show that such a nonextensive statistical effect can be very
relevant in many nuclear astrophysical problems.Comment: 8 pages, Proceedings of the X Convegno su Problemi di Fisica Nucleare
Teoric
Nonextensive statistical effects on the relativistic nuclear equation of state
Following the basic prescriptions of the Tsallis' nonextensive
thermodynamics, we study the relativistic nonextensive thermodynamics and the
equation of state for a perfect gas at the equilibrium. The obtained results
are used to study the relativistic nuclear equation of state in the hadronic
and in the quark-gluon plasma phase. We show that small deviations from the
standard extensive statistics imply remarkable effects into the shape of the
equation of state.Comment: Contribution to International Workshop on: Trends and Perspectives in
Extensive and Non-Extensive Statistical Mechanics (in Honour to the q-60th
Birthday of Constantino Tsallis) November 19-21, 2003, Angra dos Reis,
Brazil. 8 pages including 2 figure
Dynamic Trace-Based Data Dependency Analysis for Parallelization of C Programs
Writing parallel code is traditionally considered a difficult task, even when it is tackled from the beginning of a project. In this paper, we demonstrate an innovative toolset that faces this challenge directly. It provides the software developers with profile data and directs them to possible top-level, pipeline-style parallelization opportunities for an arbitrary sequential C program. This approach is complementary to the methods based on static code analysis and automatic code rewriting and does not impose restrictions on the structure of the sequential code or the parallelization style, even though it is mostly aimed at coarse-grained task-level parallelization. The proposed toolset has been utilized to define parallel code organizations for a number of real-world representative applications and is based on and is provided as free source
Nonextensive statistics in stellar plasma and solar neutrinos
Nonextensive and quantum uncertainty effects (related to the quasiparticles
composing the stellar core) have strong influence on the nuclear rates and, of
course, affect solar neutrino fluxes. Both effects do coexist and are due to
the frequent collisions among the ions. The weakly nonextensive nature of the
solar core is confirmed. The range of predictions for the neutrino fluxes is
enlarged and the solar neutrino problem becomes less dramatic.Comment: 4 pages. Proc. of TAUP99, Sept. 6-10 1999, Paris. To appear in Nucl.
Phys. B, Proc. Supp
Color Superconductivity in Compact Stars and Gamma Ray Bursts
We study the effects of color superconductivity on the structure and
formation of compact stars. We show that it is possible to satisfy most of
recent observational boundaries on masses and radii if a diquark condensate
forms in a hybrid or a quark star. Moreover, we find that a huge amount of
energy, of the order of erg, can be released in the conversion from a
(metastable) hadronic star into a (stable) hybrid or quark star, if the
presence of a color superconducting phase is taken into account. Accordingly to
the scenario proposed in Astrophys.J.586(2003)1250, the energy released in this
conversion can power a Gamma Ray Burst. This mechanism can explain the recent
observations indicating a delay, of the order of days or years, between a few
Supernova explosions and the subsequent Gamma Ray Burst.Comment: 15 pages, 4 figures, 1 tabl
Nonextensive statistical effects in the quark-gluon plasma formation at relativistic heavy-ion collisions energies
We investigate the relativistic equation of state of hadronic matter and
quark-gluon plasma at finite temperature and baryon density in the framework of
the non-extensive statistical mechanics, characterized by power-law quantum
distributions. We impose the Gibbs conditions on the global conservation of
baryon number, electric charge and strangeness number. For the hadronic phase,
we study an extended relativistic mean-field theoretical model with the
inclusion of strange particles (hyperons and mesons). For the quark sector, we
employ an extended MIT-Bag model. In this context we focus on the relevance of
non-extensive effects in the presence of strange matter.Comment: 12 pages, 5 figure
Temperature dependence of modified CNO nuclear reaction rates in dense stellar plasmas
We study the dependence of the CNO nuclear reaction rates on temperature, in
the range of K, the typical range of temperature evolution from
a Sun-like star towards a white dwarf. We show that the temperature dependence
of the CNO nuclear reaction rates is strongly affected by the presence of
non-extensive statistical effects in the dense stellar core. A very small
deviation from the Maxwell-Boltzmann particle distribution implies a relevant
enhancement of the CNO reaction rate and could explain the presence of heavier
elements (e.g. Fe, Mg) in the final composition of a white dwarf core. Such a
behavior is consistent with the recent experimental upper limit to the fraction
of energy that the Sun produces via the CNO fusion cycle.Comment: Presented at NEXT2003 (Second International Conference on "News and
Expectations in Thermostatistics"), Villasimius (Cagliari)- Italy in 21-28
September 2003. 7 pages including 3 figure
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