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bulk viscosity of hot dense Quark matter in the PNJL model

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Chinese Physics C 2014年第5期38卷 23-27页

作者：肖诗松郭盼盼张乐侯德富 Department of Computer Science Central China Normal University Institute of Particle Physics Central China Normal University

Starting from the Kubo formula and the QCD low energy theorem, we study the the bulk viscosity of hot dense quark matter in the PNJL model from the equation of state. We show that the bulk viscosity has a sharp peak near the chiral phase transition, and that the ratio of bulk viscosity over entropy rises dramatically in the vicinity of the phase transition. These results agree with those from the lattice and other model calculations. In addition, we show that the increase of chemical potential raises the bulk viscosity.

关键词： bulk viscosity Kubo formula PNJL model

bulk viscosity for interacting strange quark matter and r-mode instability windows for strange stars

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Chinese Physics C 2021年第1期45卷 341-354页

作者： Jian-Feng Xu Dong-Biao Kang Guang-Xiong Peng Cheng-Jun Xia School of Physics Electrical Engineering An Yang Normal UniversityAnYang 455000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Synergetic Innovation Center for Quantum Effects and Application Hunan Normal UniversityChangsha 410081China School of Information Science and Engineering Ningbo Tech UniversityNingbo 315100China

We investigate the bulk viscosity of strange quark matter in the framework of the equivparticle model,where analytical formulae are obtained for certain temperature ranges,which can be readily applied to those with various quark mass *** the case of adopting a quark mass scaling with both linear confinement and perturbative interactions,the obtained bulk viscosity increases by 1-2 orders of magnitude compared with those in bag model *** an enhancement is mainly due to the large quark equivalent masses adopted in the equivparticle model,which are essentially attributed to the strong interquark interactions and are related to the dynamical chiral symmetry breaki *** to the high bulk viscosity,the predicted damping time of oscillatio ns for a can on ical 1.4 M⊙ strange star is less than one millisecond,which is shorter than previous ***,the obtained r-mode instability window for the canonical strange stars well accommodates the observational frequencies and temperatures for pulsars in low-mass X-ray binaries(LMXBs).

关键词： strange quark matter equivparticle model bulk viscosity R-mode instability window

Shear and bulk viscosity of high-temperature gluon plasma

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Chinese Physics C 2018年第6期42卷 59-66页

作者： Le Zhang De-Fu Hou Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics(MOE) Central China Normal UniversityWuhan 430079China The College of Post and Telecommunication Wuhan Institute of TechnologyWuhan 430070China

We calculate the shear viscosity（η） and bulk viscosity（ζ） to entropy density（s） ratios η/s and ζ/s of a gluon plasma system in kinetic theory, including both the elastic gg←→gg forward scattering and the inelastic soft gluon bremsstrahlung gg←→ggg processes. Due to the suppressed contribution to η and ζ in the gg←→gg forward scattering and the effective g←→gg gluon splitting, Arnold, Moore and Yaffe（AMY） and Arnold, Dogan and Moore（ADM） have got the leading order computations for η and ζ in high-temperature QCD matter. In this paper, we calculate the correction to η and ζ in the soft gluon bremsstrahlung gg←→ggg process with an analytic *** find that the contribution of the collision term from the gg←→ggg soft gluon bremsstrahlung process is just a small perturbation to the gg←→gg scattering process and that the correction is at～ 5% level. Then, we obtain the bulk viscosity of the gluon plasma for the number-changing process. Furthermore, our leading-order result for bulk viscosity is the formula ζ∝（αs^2 T^3）/（lnαs^-1） in high-temperature gluon plasma.

关键词： shear viscosity bulk viscosity entropy density high-temperature gluon plasma soft gluon bremsstrahlung

Effects of bulk viscosity on hadron spectra and the Hanbury-Brown Twiss radius by causal viscous hydrodynamics

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Chinese Physics B 2009年第11期18卷 4786-4790页

作者：李建伟马余刚马国亮 Shanghai Institute of Applied Physics Chinese Academy of Sciences Graduate School of the Chinese Academy of Sciences

The particle spectra and Hanbury-Brown Twiss （HBT） radius of Au＋Au collisions at RHIC energy are investigated by a hydrodynamical expanding source with both shear and bulk viscosities （ζ）. With a large width of the ratio of ζ to entropy density s, both the particle transverse momentum spectra and the ratio Rout/Raide Of HBT radii in the direction of the total transverse momentum of detected two particles （Rout） and perpendicular to both this direction and the beam direction （Rside） become a little steeper.

关键词： relativistic hydrodynamics bulk viscosity hadron spectra HBT radius

Bianchi Type-Ⅲ String Cosmological Model With bulk viscosity and Magnetic Field

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Chinese Physics Letters 2006年第7期23卷 1702-1704页

作者：王行翔 Department of Physics Anhui Normal University Wuhu 241000

The Bianchi type-Ⅲ cosmological model for a cloud string in the presence of bulk viscosity and magnetic field are presented. To obtain the determinate model it is assumed that there is an equation of state ρ = kA and the scalar of expansion is proportional to the shear scalar θ ∝ σ, which leads to a relation between metric potentials B = mC^n. The physical and geometric aspects of the model are also discussed. The model describes a shearing non-rotating continuously expanding universe with a big-bang start. In the absence of magnetic field, it reduces to the string model with bulk viscosity that was previously given in the literature.

关键词： Bianchi Type-III Magnetic Field bulk viscosity

CORRELATION OF ION-CLUSTER STRUCTURE WITH bulk viscosity AND DENSITY OF TiO_2-BEARING MOLTEN SLAG

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Acta Metallurgica Sinica(English Letters) 1992年第11期5卷 334-339页

作者： DIAO Risheng WANG Xiqing WANG Huaiyong ZHANG Rong Iron and Steel Research Institute,Panzhihua Iron and Steel Company,Sichuan,ChinaDU Hegui Northeast University of Technology,Shenyang,China Panzhihua Iron and Steel Co Panzhihua China

An approach was made to correlate the proposed model of ion-cluster structure and structural parameter of TiO_2-bearing pentan system of molten slag with ***- sults showed that an increase of ions with 4-coordination number in molten slag makes the increase of bulk viscosity and the decrease of density,while ions with 6-coordination number are the *** structural parameter proposed is so fairly interrelated to the properties of slag,that it may be available for the prediction about *** comparison with ions of 4-coordination *** is more effective than Al and Si.

关键词： TiO_2 molten slag ion-cluster bulk viscosity density

Friedmann Cosmology with a Generalized Equation of State and bulk viscosity

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Communications in Theoretical Physics 2007年第2期47卷 379-384页

作者： MENG Xin-He REN Jie HU Ming-Guang Department of Physics Nankai University Tianjin 300071 China

The universe content is considered as a non-perfect fluid with bulk viscosity and is described by a more general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. We assume the bulk viscosityis a linear combination of two terms： one is constant, and the other is proportional to the scalar expansion 0 = 3a/a. The equation of state is described as p = （γ - 1）p ＋ po, where po is a parameter. In this framework we demonstrate that this model can be used to explain the dark energy dominated universe, and different proper choices of the parameters may lead to three kinds of fates of the cosmological evolution： no future singularity, big rip, or Type-Ⅲ singularity as presented in IS. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D 71 （2005） 063004].

关键词： Friedmann cosmology equation of state bulk viscosity dark energy

Friedmann Cosmology with bulk viscosity:A Concrete Model for Dark Energy

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Communications in Theoretical Physics 2009年第8期52卷 377-382页

作者： MENG Xin-He D0U Xu Department of Physics Nankai University Tianjin 300071 China Kavli Institute for Theoretical Physics China at the Chinese Academy of Sciences （KITPC-CAS） Beijing 100190 China

The universe content is considered as a non-perfect fluid with bulk viscosity and can be described by a general equation of state （endowed some deviation from the conventionally assumed cosmic perfect fluid model）. An explicitly bulk viscosity dark energy model is proposed to confront consistently with the current observational data sets by statistical analysis and is shown consistent with （not deviated away much from） the concordant A Cold Dark Matter （CDM） model by comparing the decelerating parameter. Also we compare our relatively simple viscosity dark energy model with a more complicated one by contrast with the concordant ACDM model and find our model improves for the viscosity dark energy model building. Finally we discuss the perspectives of dark energy probes for the coming years with observations.

关键词： dark energy cosmology bulk viscosity unification of dark matter and dark energy

Singularities and Entropy in bulk viscosity Dark Energy Model

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Communications in Theoretical Physics 2011年第11期56卷 957-966页

作者：孟新河窦旭 Department of Physics Nankai University Kavli Institute of Theoretical Physics China Chinese Academy of Sciences

In this paper bulk viscosity is introduced to describe the effects of cosmic non-perfect fluid on the cosmos evolution and to build the unified dark energy （DE） with （dark） matter models. Also we derive a general relation between the bulk viscosity form and Hubble parameter that can provide a procedure for the viscosity DE model building. Especially, a redshift dependent viscosity parameter ζ ∝ λ0 ＋λ1（1 ＋z）n proposed in the previous work [X.H. Meng and X. Dou, Commun. Theor. Phys. B2 （2009） 377] is investigated extensively in this present work. Further more we use the recently released supernova dataset （the Constitution dataset） to constrain the model parameters. In order to differentiate the proposed concrete dark energy models from the well known ACDM model, statefinder diagnostic method is applied to this bulk viscosity model, as a complementary to the Om parameter diagnostic and the deceleration parameter analysis performed by us before. The DE model evolution behavior and tendency are shown in the plane of the statefinder diagnostic parameter pair {τ, s} as axes where the fixed point represents the A CDM model The possible singularity property in this bulk viscosity cosmology is also discussed to which we can conclude that in the different parameter regions chosen properly, this concrete viscosity DE model can have various late evolution behaviors and the late time singularity could be avoided. We also calculate the cosmic entropy in the bulk viscosity dark energy frame, and find that the total entropy in the viscosity DE model increases monotonously with respect to the scale factor evolution, thus this monotonous increasing property can indicate an arrow of time in the universe evolution, though the quantum version of the arrow of time is still very puzzling.

关键词： dark energy cosmology bulk viscosity unification of dark matter and dark energy