论文标题
在使用吸收边界条件的旋转旋转的松弛动力学中访问长时间尺度
Accessing long timescales in the relaxation dynamics of spins coupled to a conduction-electron system using absorbing boundary conditions
论文作者
论文摘要
对于弱磁场，计算了经典自旋与大传导 - 电子系统相互作用的松弛时间，该磁场最初将旋转从平衡中驱动。我们在时间尺度上追踪自旋和传导 - 电子动力学，它超过了由逆近邻居跳的特征性电子尺度，降低了五个以上的数量级。这是通过新颖的吸收边界条件结构来实现的，该边界条件采用了广义的Lindblad Master-Equation方法将传导电子紧密结合模型的边缘位点与外部浴室相结合。标准Lindblad方法吸收边界的失败可追溯到由于与浴室的耦合而最初产生的人造激发。这可以通过引入Lindblad参数矩阵并固定这些矩阵来完美抑制初始状态伪像以及向系统边界传播的物理激发的反射来纠正这一点。为电子结构的一维模型提供并讨论了数值结果。
The relaxation time of a classical spin interacting with a large conduction-electron system is computed for a weak magnetic field, which initially drives the spin out of equilibrium. We trace the spin and the conduction-electron dynamics on a time scale, which exceeds the characteristic electronic scale that is set by the inverse nearest-neighbor hopping by more than five orders of magnitude. This is achieved with a novel construction of absorbing boundary conditions, which employs a generalized Lindblad master-equation approach to couple the edge sites of the conduction-electron tight-binding model to an external bath. The failure of the standard Lindblad approach to absorbing boundaries is traced back to artificial excitations initially generated due to the coupling to the bath. This can be cured by introducing Lindblad parameter matrices and by fixing those matrices to perfectly suppress initial-state artifacts as well as reflections of physical excitations propagating to the system boundaries. Numerical results are presented and discussed for generic one-dimensional models of the electronic structure.
