1,720,984 research outputs found
Astrophysical Aspects of Neutrino Dynamics in Ultradegenerate Quark Gluon Plasma
Full text linkThe cardinal focus of the present review is to explore the role of neutrinos originating from the ultradense core of neutron stars composed of quark gluon plasma in the astrophysical scenario. The collective excitations of the quarks involving the neutrinos through the different kinematical processes have been studied. The cooling of the neutron stars as well as pulsar kicks due to asymmetric neutrino emission has been discussed in detail. Results involving calculation of relevant physical quantities like neutrino mean free path and emissivity have been presented in the framework of non-Fermi liquid behavior as applicable to ultradegenerate plasma
Dissipative Kinematics in Binary Neutron Star Mergers
No full textWe highlight the recent progress in the calculation of transport coefficients pertinent to binary neutron star mergers. Specifically, we analyze the bulk viscosity coefficient driven by both the DURCA and MURCA processes and electron transport coefficients in dense and hot plasma relevant to the merger scenario. The study considers high temperatures (T>6×1010 K) and dense environments (nB∼n0−3n0). Bulk viscosity exhibits resonant behavior, with peak values and peak positions dependent on particle interaction rates and thermodynamic susceptibilities. Susceptibilities are calculated by modeling the nuclear matter in the density functional approach. The bulk viscosity coefficient peaks at T∼1011 K, with a compression–rarefaction oscillation dissipation time scale of 20–50 ms. Electrical transports incorporate frequency-dependent dynamical screening in quantized electron–ion scattering rates. Consequently, dynamical screening reduces the maxima of electrical and thermal conductivities, shortening corresponding dissipation time scales. These results highlight the crucial role of dissipation coefficients in understanding binary neutron star mergers
Role of magnetic interactions in neutron stars
Full text linkIn this work, we present a calculation of the non-Fermi liquid correction to the specific heat of magnetized degenerate quark matter present at the core of the neutron star. The role of non-Fermi liquid corrections to the neutrino emissivity has been calculated beyond leading order. We extend our result to the evaluation of the pulsar kick velocity and cooling of the star due to such anomalous corrections and present a comparison with the simple Fermi liquid case
Dynamically screened strongly quantized electron transport in binary neutron-star merger
Full text linkWe examine electron-transport coefficients in magnetized hot and dense
electron-ion plasma relevant in binary neutron star merger simulation. We
calculate electrical and thermal conductivities in low density, high
temperature, highly magnetized plasma of binary neutron star mergers where
quantum oscillatory behavior of electrons emerge. For pronounced thermodynamic
effects, we consider zeroth Landau level population of electrons for the
calculation of conductivity. We solve Boltzmann equation in presence of
magnetic field to obtain the dissipative components of electrical and thermal
conductivities. The dissipative coefficients are formulated considering
frequency dependent dynamical screening in the quantized electron-ion
scattering rate. Numerical estimations show that the effect of dynamical
screening of photon propagator on electrical and thermal conductivities is
pronounced. We observe that dynamical screening reduces the maxima of both the
electrical and thermal conductivities by factors of thirty one and twenty
respectively leading to a reduction in the corresponding time scales of these
coefficients. The common scaling factor between electrical and thermal
conductivity is also observed to follow cubic relationship with temperature
violating Wiedemann-Franz law.Comment: Accepted in The European Physical Journal C. arXiv admin note:
substantial text overlap with arXiv:2108.1187
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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