论文标题

量子多体汉密尔顿人的代数 - 动力学理论:强烈相互作用系统的形式化方法

Algebraic-Dynamical Theory for Quantum Many-body Hamiltonians: A Formalized Approach To Strongly Interacting Systems

论文作者

Ding, Wenxin

论文摘要

非共同代数和纠缠是多体量子系统最重要的两个标志。动态扰动方法是量子多体系统最广泛使用的方法。尽管最近基于纠缠的数值方法的研究正在蓬勃发展,但传统的动态扰动方法并未从研究量子纠缠中受益。在这项工作中,我们通过结合量子代数的力量和动力学方法来制定代数动态理论(ADT),其中量子纠缠自然地作为组织原理出现。我们首先引入一个完整的操作员基集(COB),该基集(COBS)可以用纯的或混合的任意状态由COB的期望值表示。然后,我们通过Heisenberg-和Schwinger-Dyson-Motion(SDEOM)建立了从给定状态到一组完整的动态相关函数的完整映射。 COB和映射的完整性可确保ADT原则上是数学上完整的框架。将ADT应用于晶格上的多体系统时,我们发现量子纠缠是由多体棒的期望值的累积结构表示。状态的累积结构形成相关性的层次结构。更重要的是,这种静态相关层次结构是由动力相关性及其SDEOM继承的。我们建议,动态层次结构也被带入该状态的任何扰动计算中。我们以明确的例子证明了这种扰动层次结构的有效性,其中我们表明单粒子型扰动计算失败,而层次结构后的多体扰动成功。我们还讨论了ADT的计算和近似方案及其对其他强耦合理论(如Parton和从属粒子方法)的影响。

Non-commutative algebras and entanglement are two of the most important hallmarks of many-body quantum systems. Dynamical perturbation methods are the most widely used approaches for quantum many-body systems. While study of entanglement-based numerical methods are booming recently, the traditional dynamical perturbation methods have not benefited from study of quantum entanglement. In this work, we formulate an algebraic-dynamical theory (ADT) by combining the power of quantum algebras and dynamical methods in which quantum entanglement naturally emerges as the organizing principle. We start by introducing a complete operator basis set (COBS), with which an arbitrary state, either pure or mixed, can be represented by the expectation values of COBS. Then we establish a complete mapping from a given state to a complete set of dynamical correlation functions of the state through the Heisenberg- and Schwinger-Dyson-equations-of-motion (SDEOM). The completeness of COBS and the mapping ensures ADT to be a mathematically complete framework in principle. Applying ADT to many-body systems on lattices, we find that the quantum entanglement is represented by the cumulant structure of expectation values of the many-body COBS. The cumulant structure of the state forms a hierarchy in correlations. More importantly, such static correlational hierarchy is inherited by the dynamical correlations and their SDEOM. We propose that the dynamical hierarchy is also carried into any perturbative calculation on that state. We demonstrate the validity of such perturbation hierarchy with an explicit example, in which we show that a single-particle-type perturbative calculation fails while a many-body perturbation following the hierarchy succeeds. We also discuss the computation and approximation schemes of ADT and its implications to other strong coupling theories like parton and slave particle methods.

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