论文标题
用于参数泵的镁的无碰撞动力学理论
Collisionless kinetic theory for parametrically pumped magnons
论文作者
论文摘要
我们讨论了无碰撞动力学方程，描述了暴露于振荡微波场的铁磁体中镁质的非平衡动力学。以前，在所谓的“ S理论”中处理了此问题，其中在动力学方程中的碰撞积分被忽略或通过有效的放松时间在现象学上考虑到现象学上。但是，S理论尚未包括木剂凝结的可能性。此外，通常仅保留环路动量等于外部动量的术语，通常会通过保留术语来脱钩的动量积分。在这项工作中，我们批判性地检查了这些近似值的准确性，并开发了S理论的适当扩展。我们表明，这些扩展可以显着改变木元分布的时间演化。
We discuss collisionless kinetic equations describing the non-equilibrium dynamics of magnons in a ferromagnet exposed to an oscillating microwave field. Previously, this problem has been treated within the so-called "S-theory" where the collision integral in the kinetic equation for the magnon distribution is either neglected or taken into account phenomenologically via an effective relaxation time. However, the possibility of magnon condensation has not been included in S-theory. Moreover, the momentum integrations appearing in the magnon self-energies are usually decoupled by retaining only the term where the loop momentum is equal to the external momentum. In this work we critically examine the accuracy of these approximations and develop the proper extensions of S-theory. We show that these extensions can significantly modify the time evolution of the magnon distribution.
