论文标题
相对论的理想气体的能量摩孔密度和压力关系，并具有大量运动
Energy-momentum density and pressure relations for a relativistic ideal gas with a bulk motion
论文作者
论文摘要
我们在这里从第一原理中得出了完美流体的能量摩孔密度，以理想的分子气体的形式，在惯性框架中，流体具有大量运动。我们从在流体的其余框架中的能量密度和压力的简单表达式开始，其中流体成分（气体分子）可能具有随机运动，但没有散装运动。从分子速度向量的洛伦兹转化，沿流体的其余框架沿不同方向移动，我们在惯性框架中计算了它们的能量摩托词和数量密度相对于液体的休息框。由此，我们在具有散装运动的框架内到达流体的能量密度。这样，我们明确说明了几个奇怪的压力依赖性术语如何在具有批量运动的完美流体的能量摩托密度中出现。除了理想的分子气外，我们还计算了光子气体的能量摩孔密度，当然，这与具有超偏置性随机运动的分子气体获得的能量摩孔密度表达相匹配。
We derive here, from first principles, the energy-momentum densities of a perfect fluid, in the form of an ideal molecular gas, in an inertial frame where the fluid possesses a bulk motion. We begin from the simple expressions for the energy density and pressure of a perfect fluid in the rest frame of the fluid, where the fluid constituents (gas molecules) may possess a random motion, but no bulk motion. From a Lorentz transformation of the velocity vectors of molecules, moving along different directions in the rest frame of the fluid, we compute their energy-momentum vectors and number densities in an inertial frame moving with respect to the rest frame of the liquid. From that we arrive at the energy-momentum density of the fluid in a frame where it has a bulk motion. This way we explicitly demonstrate how a couple of curious pressure-dependent terms make appearance in the energy-momentum density of a perfect fluid having a bulk motion. In addition to an ideal molecular gas, we compute the energy-momentum density for a photon gas also, which of course matches with the energy-momentum density expression obtained for a molecular gas having ultra-relativistic random motion.
