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 cluster size of the condensations
from the early growth of density correlation functions. Expectations are that
hot nuclear matter behaves unstable around &rho / b &asymp / &rho / 0/4 (below the saturation
density) and at low temperatures. We therefore present our results at low temperature
T=1 MeV and at higher temperature T=5 MeV, and also at a lower
initial baryon density &rho / b = 0.2 &rho / 0 and a higher value &rho / b = 0.4 &rho / 0 where unstable
behavior is within them.
Calculations in density-dependent model are compared with the other calculations
obtained in a relativistic non-linear model and in a Skyrme type nonivrelativistic model. Our results are consistent with them. Qualitatively similar
results show that the physics of the quantities are model-independent. The size
of clusterization is estimated in two ways, by using half-wavelength of the most
unstable mode and from the width of correlation function at half maximum. Furthermore,
the average speed of condensing fragments during the initial phase of
spinodal decomposition are determined by using the current density correlation
functions.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613473/index.pdf |
| Date | 01 August 2011 |
| Creators | Danisman, Betul |
| Contributors | Yilmaz, Osman |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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