NESSi: The Non-Equilibrium Systems Simulation package
NESSi: The Non-Equilibrium Systems Simulation package
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DOI：
10.1016/j.cpc.2020.107484
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发表时间：
2019-10
期刊：
影响因子：
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通讯作者：
M. Schüler;D. Golež;Y. Murakami;N. Bittner;Andreas Hermann;H. Strand;P. Werner;M. Eckstein
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文献类型：
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作者：
M. Schüler;D. Golež;Y. Murakami;N. Bittner;Andreas Hermann;H. Strand;P. Werner;M. Eckstein
相关多粒子系统的非平衡动力学与分子系统和固体的泵探测实验以及输运性质和弛豫过程的理论研究有关。非平衡态绿色函数是研究量子多粒子系统中非平衡态相互作用效应的有力工具，也是提取物理相关信息解释实验的有力工具。我们提出的开源软件包NESSi（非平衡系统模拟包），它允许执行多体动力学模拟的基础上，L形Kadanoff-Baym轮廓的绿色的功能。NESSi包含库libcntr，该库实现了对这些非平衡绿色函数的基本操作工具，用于构建费曼图，以及用于解决涉及轮廓绿色函数的积分和积分微分方程。该库采用了离散化的Kadanoff-Baym轮廓到时间N点和高阶的集成例程的实现。总的积分误差可达O（N− 7），这一点很重要，因为数值工作量至少会随着模拟时间的增加而增加三次方。在倒易空间上的分布式存储器并行化允许大规模模拟晶格系统。我们提供了一个例子程序的集合，从简单的两级系统的动力学相关的问题，在当代凝聚态物理学，包括哈伯德集群和哈伯德或荷尔斯泰因晶格模型。libcntr库是基于强耦合微扰杂质求解器的非平衡动力学平均场理论计算的后续软件包的基础。程序摘要程序标题：NESSi CPC库程序文件链接：http：//dx。doi。org/10.17632/973crf9hgd。1许可条款：MPL v2。0编程语言：C++，python外部例程/库：cmake，eigen 3，hdf 5（可选），mpi（可选），omp（可选）问题性质：求解Kadanoff-Baym轮廓上的时间相关绿色函数的运动方程。解决方法：高阶解决方法的积分和积分微分方程的Kadanoff-Baym轮廓。
The nonequilibrium dynamics of correlated many-particle systems is of interest in connection with pump–probe experiments on molecular systems and solids, as well as theoretical investigations of transport properties and relaxation processes. Nonequilibrium Green’s functions are a powerful tool to study interaction effects in quantum many-particle systems out of equilibrium, and to extract physically relevant information for the interpretation of experiments. We present the open-source software package NESSi (The Non-Equilibrium Systems Simulation package) which allows to perform many-body dynamics simulations based on Green’s functions on the L-shaped Kadanoff–Baym contour. NESSi contains the library libcntr which implements tools for basic operations on these nonequilibrium Green’s functions, for constructing Feynman diagrams, and for the solution of integral and integro-differential equations involving contour Green’s functions. The library employs a discretization of the Kadanoff–Baym contour into time N points and a high-order implementation of integration routines. The total integrated error scales up to O (N− 7), which is important since the numerical effort increases at least cubically with the simulation time. A distributed-memory parallelization over reciprocal space allows large-scale simulations of lattice systems. We provide a collection of example programs ranging from dynamics in simple two-level systems to problems relevant in contemporary condensed matter physics, including Hubbard clusters and Hubbard or Holstein lattice models. The libcntr library is the basis of a follow-up software package for nonequilibrium dynamical mean-field theory calculations based on strong-coupling perturbative impurity solvers. Program summary Program Title: NESSi CPC Library link to program files: http://dx. doi. org/10.17632/973crf9hgd. 1 Licensing provisions: MPL v2. 0 Programming language: C++, python External routines/libraries: cmake, eigen3, hdf5 (optional), mpi (optional), omp (optional) Nature of problem: Solves equations of motion of time-dependent Green’s functions on the Kadanoff–Baym contour. Solution method: Higher-order solution methods of integral and integro-differential equations on the Kadanoff–Baym contour.