移位逆Lanczos算法在输运问题非平衡格林函数中的应用
Application of the shift-invert Lanczos algorithm to a non-equilibrium Green function for transport problems
AI总结:
针对非平衡格林函数方法求解多体输运问题时大矩阵求逆计算成本高的问题,提出采用移位逆Lanczos方法,经简单模型与核裂变哈密顿量测试,维度66103下计算时间较直接计算缩短33倍。
摘要:
非平衡格林函数理论及相关方法被广泛用于描述多体系统中的输运现象,但这类方法通常需要对大型矩阵进行求逆,计算成本高昂。本文表明移位逆Lanczos方法可大幅降低计算量。我们将该方法应用于两个测试问题:一个简单模型哈密顿量,以及一个更贴近实际的核裂变哈密顿量。对于维度为66103的哈密顿量,我们发现与直接计算格林函数相比,计算时间缩短了33倍。
英文摘要:
Non-equilibrium Green's function theory and related methods are widely used to describe transport phenomena in many-body systems, but they often require a costly inversion of a large matrix. We show here that the shift-invert Lanczos method can dramatically reduce the computational effort. We apply the method to two test problems, namely a simple model Hamiltonian and to a more realistic Hamiltonian for nuclear fission. For a Hamiltonian of dimension 66103 we find that the computation time is reduced by a factor of 33 compared to the direct calculation of the Green's function.
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