标题： 粘性流体解对场方程以及减速参数的再探讨 显示英文标题

标题： Bulk Viscous Solutions to the Field Equations and the Deceleration Parameter-Revisited

摘要： 我们采用哈勃参数的一种形式，以生成多个满足爱因斯坦场方程的解，在有整体黏性流体存在的情况下，宇宙学常数和引力常数均为可变的。所用的哈勃定律使减速参数取为恒定值。 在罗伯逊-沃克时空内提出了一类新的解。假设整体黏性系数是质量密度的幂函数。 对于一类解，减速参数为负值，这与超新星Ia的观测结果一致。 显示英文摘要

摘要： We utilise a form for the Hubble parameter to generate a number of solutions to the Einstein field equations with variable cosmological constant and variable gravitational constant in the presence of a bulk viscous fluid. The Hubble law utilised yields a constant value for the deceleration parameter. A new class of solutions is presented in the Robertson-Walker spacetimes. The coefficient of bulk viscosity is assumed to be a power function of the mass density. For a class of solutions, the deceleration parameter is negative which is consistent with the supernovae Ia observations.