Quantal description of spinodal instabilities in a symmetric nuclear matter

Acar Çakırca, Fatma
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 growth rates of the unstable collective modes are calculated and the boundary of the spinodal region is obtained from the phase diagram for different initial conditions at different asymmetries. In general, growth of instabilities becomes slower with increasing charge asymmetry. The baryon density correlation function that includes information about the initial size of the condensing fragments is also calculated for the collective modes. In the non-relativistic framework, a complete treatment of density correlation functions is presented by including collective modes and non-collective modes as well. The growth of density fluctuations in the spinodal region of asymmetric nuclear matter is investigated in the stochastic mean-field approach based on Skyrme-type effective interactions. It is possible to derive nearly analytical expression for the density correlation function in the linear response limit of the stochastic mean-field approach, which involves a counter integration over the complex frequency plane. In order to provide a complete description of the correlation function,we evaluate collective and also non-collective poles in numerical calculations. These investigations will allow us to obtain more accurate information about the condensation mechanism and early evolution of liquid-gas phase transformation of nuclear matter. 


Spinodal instabilities in symmetric nuclear matter within a nonlinear relativistic mean-field approach
Acar, Fatma; Yılmaz, Osman; Department of Physics (2011)
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 len...
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
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...
Investigations of spinodal dynamics in asymmetric nuclear matter within a stochastic relativistic model
Yılmaz, Osman; ACAR, FERİDE PINAR; Saatci, S.; GÖKALP, AHMET (Springer Science and Business Media LLC, 2013-03-01)
Early development of spinodal instabilities and density correlation functions in asymmetric nuclear matter are investigated in the stochastic extension of the Walecka-type relativistic mean field including coupling with rho meson. Calculations are performed under typical conditions encountered in heavy-ion collisions and in the crusts of neutron stars. In general, growth of instabilities occur relatively slower for increasing charge asymmetry of matter. At higher densities around rho = 0.4 rho(0) fluctuatio...
Measurement of the differential cross-sections of inclusive, prompt and non-prompt J/psi production in proton-proton collisions at root s=7 TeV
Aad, G.; et. al. (Elsevier BV, 2011-09-21)
The inclusive production cross-section and fraction of mesons produced in B-hadron decays are measured in proton–proton collisions at with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the , using 2.3 pb−1 of integrated luminosity. The cross-section is measured from a minimum of 1 GeV to a maximum of 70 GeV and for rapidities within giving the widest reach of any measurement of production to date. The differential production cross-sections of prompt and non-pr...
Citation Formats
F. Acar Çakırca, “Quantal description of spinodal instabilities in a symmetric nuclear matter,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.