Transport coefficients and resonances for a meson gas in chiral perturbation theory

Fernández-Fraile, D.; Nicola, Á. Gómez

doi:10.1140/epjc/s10052-009-0935-0

Cited by 108 publications

(249 citation statements)

References 59 publications

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“…For even smaller T , η/s increases again monotonically as T → T + c . This picture is qualitatively in agreement with model predictions for the confined phase reporting a monotonically decreasing η/s for T → T − c [118][119][120]. For both fits, the ratio η/s is found to be significantly smaller than unity in a temperature region around its minimum, which is in contrast to naive extrapolations of pure pQCD results.…”

Section: The Shear Viscositysupporting

confidence: 88%

“…In fact, the observed possible rapid increase of η/s with decreasing T close to T c as well as the behavior with T in the confined phase [118][119][120] call for refinements in viscous hydrodynamic simulations [133][134][135]. The smallness of ζ /s over a wide range of T , in contrast, could suggest that the impact of bulk viscous effects is less important.…”

Section: The Bulk Viscositymentioning

confidence: 97%

“…This, however, seems to be unfavored by recent results obtained for T T c in the confined phase [118][119][120].…”

Section: T C η/S Rises To Quite Large Values For T → T +mentioning

confidence: 98%

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Shear and bulk viscosities of the gluon plasma in a quasiparticle description

2011

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Shear and bulk viscosities of deconfined gluonic matter are investigated within an effective kinetic theory by describing the strongly interacting medium phenomenologically in terms of quasiparticle excitations with medium-dependent self-energies. We show that the resulting transport coefficients reproduce the parametric dependencies on temperature and coupling obtained in perturbative QCD at large temperatures and small running coupling. The extrapolation into the nonperturbative regime results in a decreasing specific shear viscosity with decreasing temperature, exhibiting a minimum in the vicinity of the deconfinement transition, while the specific bulk viscosity is sizable in this region, falling off rapidly with increasing temperature. The temperature dependence of specific shear and bulk viscosities found within this quasiparticle description of the pure gluon plasma is in agreement with available lattice QCD results.

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Section: The Shear Viscositysupporting

confidence: 88%

Section: The Bulk Viscositymentioning

confidence: 97%

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Shear and bulk viscosities of the gluon plasma in a quasiparticle description

2011

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“…It is more than an order of magnitude larger than the electrical conductivity in a pion gas [40]. It should be obvious that this determination of the electrical conductivity is sensitive to the ansatz made for the spectral function in our analysis of the correlation functions.…”

Section: A Breit-wigner + Continuum Ansatzmentioning

confidence: 85%

Thermal dilepton rate and electrical conductivity: An analysis of vector current correlation functions in quenched lattice QCD

et al. 2011

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We calculate the vector current correlation function for light valence quarks in the deconfined phase of QCD. The calculations have been performed in quenched lattice QCD at T ≃ 1.45T c for four values of the lattice cut-off on lattices up to size 128 3 × 48. This allows to perform a continuum extrapolation of the correlation function in the Euclidean time interval 0.2 ≤ τ T ≤ 0.5, which extends to the largest temporal separations possible at finite temperature, to better than 1% accuracy. In this interval, at the value of the temperature investigated, we find that the vector correlation function never deviates from the free correlator for massless quarks by more than 9%. We also determine the first two non-vanishing thermal moments of the vector meson spectral function. The second thermal moment deviates by less than 7% from the free value. With these constraints, we then proceed to extract information on the spectral representation of the vector correlator and discuss resulting consequences for the electrical conductivity and the thermal dilepton rate in the plasma phase.

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“…A list of references are [2,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], where Ref. [19] addressed high temperature perturbative QCD calculations of ζ, Refs.…”

Section: Introductionmentioning

confidence: 99%

Bulk viscosity for pion and nucleon thermal fluctuation in the hadron resonance gas model

2016

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We have calculated microscopically bulk viscosity of hadronic matter, where equilibrium thermodynamics for all hadrons in medium are described by Hadron Resonance Gas (HRG) model. Considering pions and nucleons as abundant medium constituents, we have calculated their thermal widths, which inversely control the strength of bulk viscosities for respective components and represent their in-medium scattering probabilities with other mesonic and baryonic resonances, present in the medium. Our calculations show that bulk viscosity increases with both temperature and baryon chemical potential, whereas viscosity to entropy density ratio decreases with temperature and with baryon chemical potential, the ratio increases first and then decreases. The decreasing nature of the ratio with temperature is observed in most of the earlier investigations with few exceptions. We find that the temperature dependence of bulk viscosity crucially depends on the structure of the relaxation time. Along the chemical freeze-out line in nucleus-nucleus collisions with increasing collision energy, bulk viscosity as well as the bulk viscosity to entropy density ratio decreases, which also agrees with earlier references. Our results indicate the picture of a strongly coupled hadronic medium.

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Transport coefficients and resonances for a meson gas in chiral perturbation theory

Cited by 108 publications

References 59 publications

Shear and bulk viscosities of the gluon plasma in a quasiparticle description

Shear and bulk viscosities of the gluon plasma in a quasiparticle description

Thermal dilepton rate and electrical conductivity: An analysis of vector current correlation functions in quenched lattice QCD

Bulk viscosity for pion and nucleon thermal fluctuation in the hadron resonance gas model

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