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Related papers: Shear viscosity from nuclear stopping

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With the attempts of extending the hydrodynamic framework of heavy-ion collision to proton-proton and other small and low energy systems, we are confronted with the question of how small the system can get and still be safely modelled as a…

High Energy Physics - Phenomenology · Physics 2022-12-02 Nikhil Hatwar , Madhukar Mishra

We calculate for the first time the shear viscosity of ultrarelativistic Boson systems in the presence of a Bose-Einstein condensate (BEC). Two different methods are used. One is the Grad's method of moments and another is the Green-Kubo…

High Energy Physics - Phenomenology · Physics 2019-11-19 Zhengyu Chen , Carsten Greiner , Zhe Xu , Pengfei Zhuang

The reverse perturbation method [Phys. Rev. E 59, 4894 (1999)] for shearing simple liquids and measuring their viscosity is extended to the Vicsek-model (VM) of active particles [Phys. Rev. Lett. 75, 1226 (1995)] and its metric-free…

Soft Condensed Matter · Physics 2019-10-23 Arash Nikoubashman , Thomas Ihle

Shear relaxation and dynamic density fluctuations are studied within a Rouse model, generalized to include the effects of permanent random crosslinks. We derive an exact correspondence between the static shear viscosity and the resistance…

Statistical Mechanics · Physics 2009-10-31 Kurt Broderix , Henning Loewe , Peter Mueller , Annette Zippelius

In this letter, following an extensive experimental validation, we perform constant-volume shearing simulations of non-Brownian granular suspensions using the discrete element method coupled with the lattice Boltzmann method. We choose a…

Soft Condensed Matter · Physics 2023-07-18 Zaohui Zhang , Teng Man , Herbert E. Huppert , Sergio Andres Galindo-Torres

We evaluate the viscous damping of anisotropic flow in heavy-ion collisions for arbitrary temperature-dependent shear and bulk viscosities. We show that the damping is solely determined by effective shear and bulk viscosities, which are…

Nuclear Theory · Physics 2021-04-29 Fernando G. Gardim , Jean-Yves Ollitrault

The correlation between the elliptic flow $v_2$ scaled by the impact parameter $b$ and the shear viscosity $\eta$ as well as the specific viscosity $\eta/s$, defined as the ratio of the shear viscosity to the entropy density $s$, is…

Nuclear Theory · Physics 2014-11-21 C. L. Zhou , Y. G. Ma , D. Q. Fang , G. Q. Zhang , J. Xu , X. G. Cao , W. Q. Shen

We address a discrepancy between different computations of $\eta/s$ (shear viscosity over entropy density) of hadronic matter. Substantial deviations of this coefficient are found between transport approaches mainly based on resonance…

Nuclear Theory · Physics 2018-05-16 J. -B. Rose , J. M. Torres-Rincon , A. Schäfer , D. R. Oliinychenko , H. Petersen

Nuclear stopping has been investigated in central symmetric nuclear collisions at intermediate energies. Firstly, it is found that the isotropy ratio, Riso, reaches a minimum near the Fermi energy and saturates or slowly increases depending…

Nuclear Experiment · Physics 2007-05-23 C. Escano-Rodriguez , D. Durand , A. Chbihi , J. D. Frankland , the INDRA Collaboration

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

We discuss the results of calculations of the shear viscosity and thermal conductivity of pure neutron matter, carried out within the Landau-Abrikosov-Khalatnikov formalism. The probability of neutron-neutron collisions in the nuclear…

Nuclear Theory · Physics 2010-04-06 Omar Benhar , Artur Polls , Marco Valli , Isaac Vidana

We explore the viscosities of a photon gas by means of the Euler-Heisenberg effective theory and quantum electrodynamics at zero electron chemical potential. We find parametric estimates that show a very large shear viscosity and an…

High Energy Physics - Phenomenology · Physics 2013-09-19 Antonio Dobado , Felipe J. Llanes-Estrada , Juan M. Torres-Rincon

We investigate the temperature dependence of the shear viscosity and spin diffusion in a two-dimensional Fermi gas with contact interactions, as realized in ultra-cold atomic gases. We describe the transport coefficients in terms of a…

Quantum Gases · Physics 2012-07-16 Tilman Enss , Carolin Küppersbusch , Lars Fritz

Shear viscosity is a measure of the amount of dissipation in a simple fluid. In kinetic theory shear viscosity is related to the rate of momentum transport by quasi-particles, and the uncertainty relation suggests that the ratio of shear…

High Energy Physics - Phenomenology · Physics 2009-11-18 Thomas Schaefer , Derek Teaney

The phonon contribution to the shear viscosity $\eta$ in superfluid neutron stars is calculated by assuming neutron pairing in a $^1S_0$ channel. The shear viscosity is obtained by means of variational methods for the solution of the…

High Energy Astrophysical Phenomena · Physics 2012-06-19 Laura Tolos , Cristina Manuel

The shear viscosity of the crust might have a damping effect on the amplitude of r-modes of rotating neutron stars. This damping has implications for the emission of gravitational waves. We calculate the contribution to the shear viscosity…

Astrophysics · Physics 2008-11-26 O. L. Caballero , S. Postnikov , C. J. Horowitz , M. Prakash

We calculate the electron shear viscosity (determined by Coulomb electron collisions) for a dense matter in a wide range of parameters typical for white dwarf cores and neutron star crusts. In the density range from ~10^3 g cm^-3 to…

Astrophysics · Physics 2009-11-13 A. I. Chugunov , D. G. Yakovlev

The relation of the shear viscosity coefficient to the recently introduced transport rate is derived within relativistic kinetic theory. We calculate the shear viscosity over entropy ratio \eta/s for a gluon gas, which involves elastic gg->…

Nuclear Theory · Physics 2008-11-26 Zhe Xu , Carsten Greiner

We calculate the shear viscosity $\eta = \eta_{e\mu}+\eta_{n}$ in a neutron star core composed of nucleons, electrons and muons ($\eta_{e\mu}$ being the electron-muon viscosity, mediated by collisions of electrons and muons with charged…

Astrophysics · Physics 2009-02-20 P. S. Shternin , D. G. Yakovlev

It is by now well known that the relativistic heavy-ion collisions at RHIC, BNL have produced a strongly interacting fluid with remarkable properties, among them the lowest ever observed ratio of the coefficient of shear viscosity to…

Nuclear Theory · Physics 2010-03-19 Rajeev S. Bhalerao