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In this paper, bulk viscosity is introduced in new holographic dark energy (HDE) to describe the effects of cosmic non-perfect fluid on the evolution of the universe in modified $f(R,T)$ gravity. Assuming $f(R,T)=R+\lambda T$, where $R$ is…

General Relativity and Quantum Cosmology · Physics 2018-04-17 C P Singh , Milan Srivastava

We study a cosmological model composed of a dark energy fluid interacting with a viscous matter fluid in a spatially flat Universe. The matter component represents the baryon and dark matter and it is taken into account, through a bulk…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Arturo Avelino

Bulk viscosity may serve to damp sound waves in a system of neutrinos coupled to very light scalar particles, in the era after normal neutrino decoupling but before recombination. We calculate the bulk viscosity parameter in a minimal…

Astrophysics · Physics 2009-11-11 R. F. Sawyer

We have calculated the temperature dependence of shear $\eta$ and bulk $\zeta$ viscosities of quark matter due to quark-meson fluctuations. The quark thermal width originating from quantum fluctuations of quark-$\pi$ and quark-$\sigma$…

Nuclear Theory · Physics 2016-07-20 Sabyasachi Ghosh , Thiago C. Peixoto , Victor Roy , Fernando E. Serna , Gastão Krein

The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model. For…

High Energy Physics - Phenomenology · Physics 2022-03-15 Zhen-Yan Lu , Jian-Feng Xu , Xin-Jian Wen , Guang-Xiong Peng , Marco Ruggieri

The Eulerian cosmological fluid equations are used to study the nonlinear mode coupling of density fluctuations. We evaluate the second-order power spectrum including all four-point contributions. In the weakly nonlinear regime we find that…

Astrophysics · Physics 2009-10-22 Bhuvnesh Jain , Edmund Bertschinger

We present an analytic description of the $r$-mode instability in newly-born neutron stars, using the approximation of uniform density. Our computation is consistently accurate to second order in the angular velocity of the star. We obtain…

Astrophysics · Physics 2011-05-23 K. D. Kokkotas , N. Stergioulas

The radii of nucleon distribution, bulk density, and neutron skin in nuclei beyond the \beta-stability line are studied within the direct variational method. We evaluate the partial equation of state of finite nuclei and demonstrate that…

Nuclear Theory · Physics 2012-03-22 V. M. Kolomietz , S. V. Lukyanov , A. I. Sanzhur

For temperatures $T$ ranging from a few MeV up to TeV and energy density $\rho$ up to $10^{16}~$GeV/fm$^3$, the bulk viscosity $\zeta$ is calculated in non-perturbation (up, down, strange, charm, and bottom) and perturbation theories with…

High Energy Physics - Phenomenology · Physics 2021-10-06 Abdel Nasser Tawfik , Carsten Greiner

We have derived a set of equations to describe the thermal evolution of a neutron star which undergoes small-amplitude radial pulsations. We have taken into account, in the frame of the General Theory of Relativity, the pulsation damping…

Astrophysics · Physics 2008-11-26 M. E. Gusakov , D. G. Yakovlev , O. Y. Gnedin

We determine finite temperature corrections to the heavy-quark (static) potential as a function of the shear viscosity to entropy density ratio in a strongly coupled, large-$N_c$ conformal field theory dual to five-dimensional Gauss-Bonnet…

High Energy Physics - Phenomenology · Physics 2009-09-02 Jorge Noronha , Adrian Dumitru

We study the shear and bulk viscosity coefficients as well as the thermal conductivity as arising from the collisions among phonons in superfluid neutron stars. We use effective field theory techniques to extract the allowed phonon…

Solar and Stellar Astrophysics · Physics 2014-12-01 Laura Tolos , Cristina Manuel , Sreemoyee Sarkar , Jaume Tarrus

Novel hyperuniform materials are emerging as an active field of applied and basic research since they can be designed to have exceptional physical properties. This ubiquitous state of matter presents a hidden order that is characterized by…

Context. The overdensity inside a cosmological sub-volume and the tidal fields from its surroundings affect the matter distribution of the region. The resulting difference between the local and global power spectra is characterized by the…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-11 Gábor Rácz , István Szapudi , István Csabai

We present a simple (microscopic) model in which bulk viscosity plays a role in explaining the present acceleration of the universe. The effect of bulk viscosity on the Friedmann equations is to turn the pressure into an "effective"…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-23 Jean-Sebastien Gagnon , Julien Lesgourgues

We study the bulk viscosity of a pion gas in unitarized Chiral Perturbation Theory at low and moderate temperatures, below any phase transition to a quark-gluon plasma phase. We argue that inelastic processes are irrelevant and…

High Energy Physics - Phenomenology · Physics 2015-05-27 Antonio Dobado , Felipe J. Llanes-Estrada , Juan M. Torres-Rincon

We consider moduli fields interacting with thermalized relativistic matter. We determine the temperature dependence of their damping rate and find it is dominated by thermal effects in the high temperature regime, i.e. for temperatures…

High Energy Physics - Phenomenology · Physics 2009-11-11 Dietrich Bodeker

In this work, we study the extended viscous dark energy models in the context of matter perturbations. To do this, we assume an alternative interpretation of the flat Friedmann-Lema\^itre-Robertson-Walker Universe, through the nonadditive…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-13 W. J. C. da Silva , R. Silva

We study the shear and bulk viscosities of partonic and hadronic matter as functions of temperature T within the parton-hadron-string dynamics (PHSD) off-shell transport approach. Dynamical hadronic and partonic systems in equilibrium are…

High Energy Physics - Phenomenology · Physics 2015-06-12 V. Ozvenchuk , O. Linnyk , M. I. Gorenstein , E. L. Bratkovskaya , W. Cassing

In these lectures we discuss the uses of effective field theory in studying dense hadronic matter. We focus on two regimes in the phase diagram. At low baryon density nucleons can be described as non-relativistic point particles interacting…

Nuclear Theory · Physics 2015-06-26 Thomas Schaefer