Color Superconductivity at Moderate Density

The effect of color breaking on colored quarks' chiral condensates has been investigated at zero temperature and moderate baryon density. It is found that the influence of the diquark condensate on different colored quarks is very small.Comment: 4 pages, 1 figure in eps, talk given at XXXI International Symposium on Multiparticle Dynamics, Sept 1-7, 2001, Datong China. See http://ismd31.ccnu.edu.cn

Massive Meson Fluctuation in NJL Model

Based on the self-consistent scheme beyond mean-field approximation in the large $N_c$ expansion, including current quark mass explicitly, a general scheme of SU(2) NJL model is developed. To ensure the quark self-energy expanded in the proper order of $N_c$, an approximate internal meson propagator is deduced, which is in order of $O(1/N_c)$. In our scheme, adopting the method of external momentum expansion, all the Feynman diagrams are calculated in a unified way by only expanding the quark propagator. Our numerical results show, that different from the mean field approximation in which the explicitly chiral symmetry breaking is invisible, the effect of finite pion mass can be seen clearly when beyond mean-field approximation.Comment: 1 REVTeX file, 19 pages including 3 eps figure

On the instability of inviscid, compressible free shear layers

The linear spatial instability of inviscid compressible laminar mixing of two parallel streams, comprised of the same gas, has been investigated with respect to two-dimensional wave disturbances. The effects of the velocity ratio, temperature ratio, and the temperature profile across the shear layer have been examined. A nearly universal dependence of the normalized maximum amplification rate on the convective Mach number is found, with the normalized maximum amplification rate decreasing significantly with increasing convective Mach number in the subsonic region. These results are in accord with those of recent growth rate experiments in compressible turbulent free shear layers and other similar recent calculations

An Analytic Solution of Hydrodynamic Equations with Source Terms in Heavy Ion Collisions

The energy and baryon densities in heavy ion collisions are estimated by analytically solving a 1+1 dimensional hydrodynamical model with source terms. Particularly, a competition between the energy and baryon sources and the expansion of the system is discussed in detail.Comment: LaTeX2e, 7 pages, 4 postscript figures, submitted to Int. J. Mod. Phys.