论文标题
不均匀轴与早期宇宙中磁场的相互作用
Interaction of inhomogeneous axions with magnetic fields in the early universe
论文作者
论文摘要
我们研究量子染色体动力学相变的早期宇宙中相互作用的轴和磁场的系统，当轴获得质量时。轴和磁场都应该在空间上是不均匀的。我们得出了这些磁场的空间光谱的方程，这些方程取决于共形时间。在磁场的情况下，我们处理能量密度和磁性螺旋密度的光谱。进化方程在平均场近似中以封闭形式获得。我们选择系统的参数以及对应于逼真的原始磁场和轴的初始条件。光谱的方程系统是数值求解的。我们比较了不均匀和均匀轴的病例。在这些情况下，磁场的演变仅在较小的时间间隔内有所不同。通常，磁场主要由磁扩散驱动。我们发现，对于均匀轴的放大初始波函数发生了磁场的不稳定性。如果我们解释轴轴的不均匀性，则会抑制这种不稳定。
We study the system of interacting axions and magnetic fields in the early universe after the quantum chromodynamics phase transition, when axions acquire masses. Both axions and magnetic fields are supposed to be spatially inhomogeneous. We derive the equations for the spatial spectra of these fields, which depend on conformal time. In case of the magnetic field, we deal with the spectra of the energy density and the magnetic helicity density. The evolution equations are obtained in the closed form within the mean field approximation. We choose the parameters of the system and the initial condition which correspond to realistic primordial magnetic fields and axions. The system of equations for the spectra is solved numerically. We compare the cases of inhomogeneous and homogeneous axions. The evolution of the magnetic field in these cases is different only within small time intervals. Generally, magnetic fields are driven mainly by the magnetic diffusion. We find that the magnetic field instability takes place for the amplified initial wavefunction of the homogeneous axion. This instability is suppressed if we account for the inhomogeneity of the axion.
