Kozik Evgeny
Department of Physics, King's College London, London, UK.
Nat Commun. 2024 Sep 10;15(1):7916. doi: 10.1038/s41467-024-52000-6.
Feynman's diagrammatic series is a common language for a formally exact theoretical description of systems of infinitely-many interacting quantum particles, as well as a foundation for precision computational techniques. Here we introduce a universal framework for efficient summation of connected or skeleton Feynman diagrams for generic quantum many-body systems. It is based on an explicit combinatorial construction of the sum of the integrands by dynamic programming, at a computational cost that can be made only exponential in the diagram order on a classical computer and potentially polynomial on a quantum computer. We illustrate the technique by an unbiased diagrammatic Monte Carlo calculation of the equation of state of the 2D SU(N) Hubbard model in an experimentally relevant regime, which has remained challenging for state-of-the-art numerical methods.
费曼图级数是一种用于对无限多个相互作用量子粒子系统进行形式上精确的理论描述的通用语言，也是精确计算技术的基础。在这里，我们为通用量子多体系统的连通或骨架费曼图的高效求和引入了一个通用框架。它基于通过动态规划对被积函数之和进行显式组合构造，在经典计算机上的计算成本仅在图的阶数上呈指数增长，而在量子计算机上可能呈多项式增长。我们通过对二维SU(N)哈伯德模型在实验相关区域的状态方程进行无偏图蒙特卡罗计算来说明该技术，这对现有数值方法来说一直具有挑战性。
