论文标题
使用无碰撞流体动力学模拟宇宙中微子背景
Simulating the Cosmic Neutrino Background using Collisionless Hydrodynamics
论文作者
论文摘要
宇宙中微子背景是宇宙的重要组成部分，由于中微子颗粒的速度散布非常大，很难在宇宙学模拟中包括。我们开发了一种新的方法来模拟宇宙中微子，将费米 - 迪拉克相位空间分解为恒定速度的壳，然后使用流体动力方程将这些壳进化。选择这些无碰撞流体动力方程以匹配线性理论，自由粒子的演化并允许叠加。我们将此方法实施到信息优化的宇宙学$ n $ body Code Cube中，并证明中微子扰动可以准确解决至至少$ k \ sim1 \ h/$ mpc。与传统的$ n $ body方法相比，此技术允许中微子内中微子的内存需求最多减少$ \ sim 10^3 $。
The cosmic neutrino background is an important component of the Universe that is difficult to include in cosmological simulations due to the extremely large velocity dispersion of neutrino particles. We develop a new approach to simulate cosmic neutrinos that decomposes the Fermi-Dirac phase space into shells of constant speed and then evolves those shells using hydrodynamic equations. These collisionless hydrodynamic equations are chosen to match linear theory, free particle evolution and allow for superposition. We implement this method into the information-optimized cosmological $N$-body code CUBE and demonstrate that neutrino perturbations can be accurately resolved to at least $k\sim1\ h/$Mpc. This technique allows for neutrino memory requirements to be decreased by up to $\sim 10^3$ compared to traditional $N$-body methods.
