Spinodal instabilities in symmetric nuclear matter within a nonlinear relativistic mean-field approach

Acar, Fatma
Spinodal instability mechanism and early development of density fluctuations for symmetric nuclear matter at finite temperature are studied. A stochastic extension of Walecka-type relativistic mean-field model including non-linear self-interactions of scalar mesons with NL3 parameter set is employed in the semi-classical approximation. The growth rates of unstable collective modes are investigated below the normal density and at low temperatures. The system exhibits most unstable behavior in longer wave lengths at baryon densities ρB = 0.4 ρ0 , while most unstable behavior occurs in shorter wavelengths at lower baryon densities ρB = 0.2 ρ0 . The unstable response of the system shifts towards longer wavelengths with the increasing temperature at both densities. The early growth of the density correlation functions are calculated, which provide valuable information about the initial size of the condensation and the average speed of condensing fragments. Furthermore, the relativistic results are compared with Skyrme type non-relativistic calculations. Qualitatively similar results are found in both non-relativistic and relativistic descriptions.


Spinodal instabilities in nuclear matter in a stochastic relativistic mean-field approach
Ayik, S.; Yılmaz Tüzün, Özgül; Er, N.; Gokalp, A.; Ring, P. (American Physical Society (APS), 2009-09-01)
Spinodal instabilities and early growth of baryon density fluctuations in symmetric nuclear matter are investigated in the basis of the stochastic extension of the relativistic mean-field approach in the semiclassical approximation. Calculations are compared with the results of nonrelativistic calculations based on Skyrme-type effective interactions under similar conditions. A qualitative difference appears in the unstable response of the system: the system exhibits most unstable behavior at higher baryon d...
Quantal description of spinodal instabilities in a symmetric nuclear matter
Acar Çakırca, Fatma; Yılmaz, Osman; Ayık, Şakir; Department of Physics (2017)
Spinodal instability mechanism and early development of density fluctuations for asymmetric hot nuclear matter produced in heavy-ion collisions are investigated in non-relativistic and relativistic stochastic mean-field approaches. In relativistic approach, a stochastic extension of the relativistic mean-field approximation based on non-linear Walecka model employed in a quantal framework. The mediator rho meson is added to the Walecka model in order to investigate the isospin dependence of the system. The gro...
Spinodal instabilities in symmetric nuclear matter within a density-dependent relativistic mean-field approach
Danışman, Betül; Yılmaz, Osman; Department of Physics (2011)
The nuclear matter liquid-gas phase transition is expected to be a signal of nuclear spinodal instabilities as a result of density fluctuations. Nuclear spinodal instabilities in symmetric nuclear matter are studied within a stochastic relativistic density-dependent model in semi-classical approximation. We use two parameterization for the Lagrange density, DDME1 and TW sets. The early growth of density fluctuations is investigated by employing relativistic Vlasov equation based on QHD and discussed the clu...
Quantal diffusion approach for multinucleon transfers in Xe plus Pb collisions
Ayik, S.; Yilmaz, B.; Yılmaz, Osman; Umar, A. S. (2019-07-01)
Employing a quantal diffusion description based on the stochastic mean-field approach, we analyze the mass distribution of the primary fragments in the collisions of the Xe-136 + Pb-208 system at the bombarding energy E-c.m. = 526 MeV. This quantal approach provides a good description of the primary fragment distribution without any adjustable parameter, including the effects of shell structure
RPA instabilities in finite nuclei at low density
Jacquot, B; Colonna, M; Ayik, S; Chomaz, P (Elsevier BV, 1997-05-12)
Early development of the instabilities in a dilute nuclear source is investigated using a finite temperature quantal RPA approach for different systems, The growth rates of the unstable collective modes are determined by solving a dispersion relation, which is obtained by parametrizing the transition density in terms of its multipole moments. Under typical conditions of a dilute finite system at moderate temperatures the dispersion relation exhibits an ultraviolet cut-off. As a result, only a finite number ...
Citation Formats
F. Acar, “Spinodal instabilities in symmetric nuclear matter within a nonlinear relativistic mean-field approach,” M.S. - Master of Science, Middle East Technical University, 2011.