Waves in nuclear matter / Ondas na matéria nuclear

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Assuming that nuclear matter can be treated as a perfect fluid, we study the propagation of perturbations in the baryon density. The equation of state is derived from a relativistic mean field model, which is a variant of the non-linear Walecka model. The expansion of the Euler and continuity equations of relativistic hydrodynamics around equilibrium configurations leads to differential equations for the density perturbation. We solve them numerically for linear and spherical perturbations and follow the propagation of the initial pulses. For linear perturbations we find single soliton solutions and solutions with one or more solitons followed by ``radiation. Depending on the equation of state a strong damping may occur. We consider also the evolution of perturbations in a medium without dispersive effects. In this case we observe the formation and breaking of shock waves. We study all these equations also for matter at finite temperature. Our results may be relevant for the analysis of RHIC data. They suggest that the shock waves formed in the quark gluon plasma phase may survive and propagate in the hadronic phase. We also study the non-linear wave equation for pertubations in baryon density and energy density in quark-gluon-plasma (QGP). Under certains conditions solitons may exist in QGP. Finally we discuss alternatives methods for solving non-linear differential equations.

ASSUNTO(S)

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