Calculation of relaxation times in nuclear matter

Abu-Samreh, M. M.; Köhler, H.S.

doi:10.1016/0375-9474(93)90333-s

Cited by 12 publications

(7 citation statements)

References 10 publications

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“…Many methods in the literature have been used to study the viscosity [12,15,18,24], among which directly using Green-Kubo formulas is the first-principle way of the study [25]. In the present study the relaxation time approach is used [26,27]. This approach is helpful in studying how the Pauli blocking, in-medium cross sections and in-medium effective masses will affect the shear viscosity and can give qualitative ideas how the shear viscosity changes with density, temperature and isospin asymmetry of the nuclear matter.…”

Section: Introductionmentioning

confidence: 99%

Specific viscosity of neutron-rich nuclear matter from a relaxation time approach

2011

Phys. Rev. C

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The specific viscosity of neutron-rich nuclear matter is studied from the relaxation time approach using an isospin-and momentum-dependent interaction and the nucleon-nucleon cross sections taken as those from the experimental data modified by the in-medium effective masses as used in the IBUU transport model calculations. The relaxation time of neutrons is larger while that of protons is smaller in neutron-rich nuclear matter compared with that in symmetric nuclear matter, and this leads to a larger specific viscosity in neutron-rich nuclear matter. In addition, the specific viscosity decreases with increasing temperature because of more frequent collisions and weaker Pauli blocking effect at higher temperatures. At lower temperatures the specific viscosity increases with increasing density due to the Pauli blocking effect, while at higher temperatures it slightly decreases with increasing density as a result of smaller in-medium effective masses at higher densities.

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Section: Introductionmentioning

confidence: 99%

Specific viscosity of neutron-rich nuclear matter from a relaxation time approach

2011

Phys. Rev. C

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“…The relaxation times given by Eqs. ( 37) and (47) can agree together at zero temperature if the magnitude of K B is equal to the value K 0 = (hω/α)(A/(gπ)) 3 . Here, K 0 ≡ 70.9hω/α ≃ 220 MeV 3 for giant isovector dipole resonances in heavy nuclei, when hω ≃ 13 M eV , g = A/13 and α = α = 4.18 M eV .…”

Section: Semiclassical Kinetic Equation Approachmentioning

confidence: 83%

“…The relaxation times given by Eqs. (37) and (47) 3 . It means that in cold nuclei the relaxation times for the GDR within doorway state mechanism are not too different from those obtained within the transport approach.…”

Section: Doorway State Mechanism In Heated Nucleimentioning

confidence: 99%

“…The damping of the collective excitations as well as transport coefficients for viscosity and heat conductivity are strongly governed by the particle collisions. The relaxation time method is widely used as the simplest and rather accurate approach for simulation of the collisional relaxation rate λ c ∝ 1/τ , where τ is the so-called relaxation time [1,2,3]. Relaxation time method can be applied to description of the decay rate of arbitrary mode of motion, but an explicit form of the relaxation time depends on specific features of the mode.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Two-Body Relaxation Times in Heated Nuclei

Plujko

2001

Nuclear Structure Physics

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The retardation and temperature effects in two-body collisions are studied. The collision integral with retardation effects is obtained on the base of the Kadanoff-Baym equations for Green functions in a form with allowance for reaching the local equilibrium system. The collisional relaxation times of collective vibrations are calculated using both the transport approach and doorway state mechanism with hierarchy of particle-hole configurations in heated nuclei. The relaxation times of the kinetic method are rather slowly dependent on multipolarity of the Fermi surface distortion and mode of the collective motion. The dependence of the relaxation times on temperature as well as on frequency of collective vibrations is considered and compared. It is shown that variations of the in-medium twobody cross-sections with energy lead to non-quadratic dependence of the collisional relaxation time both on temperature and on collective motion frequency.

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“…The collision integral can be used to calculate collisional relaxation times governing the dissipative properties of different physical quantities [2,4,9,10,11,12,24,25,26]. Below we calculate relaxation times, τ…”

Section: Calculations Of the Relaxation Times And Nuclear Matter Viscmentioning

confidence: 99%

Non-Markovian collision integral in Fermi systems

Plujko¹,

Ezhov²,

Gorbachenko³

et al. 2002

J. Phys.: Condens. Matter

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The non-Markovian collision integral is obtained on the base of the KadanoffBaym equations for Green functions in a form with allowance for small retardation effects. The collisional relaxation times and damping width of the giant isovector dipole resonances in nuclear matter are calculated. For an infinite Fermi liquid the dependence of the relaxation times on the collective vibration frequency and the temperature corresponds to the Landau's prescription.

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Calculation of relaxation times in nuclear matter

Cited by 12 publications

References 10 publications

Specific viscosity of neutron-rich nuclear matter from a relaxation time approach

Specific viscosity of neutron-rich nuclear matter from a relaxation time approach

Investigation of Two-Body Relaxation Times in Heated Nuclei

Non-Markovian collision integral in Fermi systems

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