内容简介
The purpose of this book is to provide an introduction to the applications of quantum field theoretic methods to systems out of equilibrium. The reason for adding a book on the subject of quantum field theory is two-fold: the presentation is, to my knowledge, the first to extensively present and apply to non-equilibrium phenomena the real-time approach originally developed by Schwinger, and subsequently applied by Keldysh and others to derive transport equations. Secondly, the aim is to show the universality of the method by applying it to a broad range of phenomena. The book should thus not just be of interest to condensed matter physicists, but to physicists in general as the method is of general interest with applications ranging the whole scale from high-energy to soft condensed matter physics. The universality of the method, as testified by the range of topics covered, reveals that the language of quantum fields is the universal description of fluctuations, be they of quantum nature, thermal or classical stochastic. The book is thus intended as a contribution to unifying the languages used in separate fields of physics, providing a universal tool for describing non-equilibrium states.
内页插图
目录
Preface
1 Quantum fields
1.1 Quantum mechanics
1.2 N-particle system
1.2.1 Identical particles
1.2.2 Kinematics of fermions
1.2.3 Kinematics of bosons
1.2.4 Dynamics and probability current and density
1.3 Fermi field
1.4 Bose field
1.4.1 Phonons
1.4.2 Quantizing a classical field theory
1.5 Occupation number representation
1.6 Summary
2 Operators on the multi-particle state space
2.1 Physical observables
2.2 Probability density and number operators
2.3 Probability current density operator
2.4 Interactions
2.4.1 Two-particle interaction
2.4.2 Fermio boson interaction
2.4.3 Electron-phonon interaction
2.5 The statistical operator
2.6 Summary
3 Quantum dynamics and Greens functions
3.1 Quantum dynamics
3.1.1 The SchrSdinger picture
3.1.2 The Heisenberg picture
3.2 Second quantization
3.3 Greens functions
3.3.1 Physical properties and Greens functions
3.3.2 Stable of one-particle Greens functions
3.4 Equilibrium Greens functions
3.5 Summary
4 Non-equilibrium theory
4.1 The non-equilibrium problem
4.2 Ground state formalism
4.3 Closed time path formalism
4.3.1 Closed time path Greens function
4.3.2 Non-equilibrium perturbation theory
4.3.3 Wicks theorem
4.4 Non-equilibrium diagrammatics
4.4.1 Particles coupled to a classical field
4.4.2 Particles coupled to a stochastic field
4.4.3 Interacting fermions and bosons
4.5 The self-energy
4.5.1 Non-equilibrium Dyson equations
4.5.2 Skeleton diagrams
4.6 Summary
5 Real-time formalism
5.1 Real-time matrix representation
5.2 Real-time diagrammatics
5.2.1 Feynman rules for a scalar potential
5.2.2 Feynman rules for interacting bosons and fermions
5.3 Triagonal and symmetric representations
5.3.1 Fermion-boson coupling
5.3.2 Two-particle interaction
5.4 The real rules: the RAK-rules
5.5 Non-equilibrium Dyscn equations
5.6 Equilibrium Dyscn equation
5.7 Real-time versus imaginary-time formalism
5.7.1 Imaginary-time formalism
5.7.2 Imaginary-time Greens functions
5.7.3 Analytical continuation procedure
5.7.4 Kadanoff-Baym equations
5.8 Summary
6 Linear response theory
6.1 Linear response
6.1.1 Density re~,ponse
6.1.2 Current response
6.1.3 Ccnductivity tensor
6.1.4 Ccnductance
6.2 Linear response cf Greens functions
6.3 Properties cf respone hmctions
6.4 Stability cf the thermal equilibrium ,tate
6.5 Fluctuation-dissipation theorem
6.6 Time-reversal symmetry
6.7 Scattering and correlation functions
6.8 Summary
7 Quantum kinetic equations
7.1 Left-right subtracted Dyson equation
7.2 Wigner or mixed coordinates
7.3 Gradient approximation
7.3.1 Spectral weight function
7.3.2 Quasi-particle approximation
7.4 Impurity scattering
7.4.1 Boltzmannian motion in a random potential
7.4.2 Brownian motion
7.5 Quasi-classical Greens function technique
7.5.1 Electron-phonon interaction
7.5.2 Renormalization of the a.c. conductivity
7.5.3 Excitation representation
7.5.4 Particle conservation
7.5.5 Impurity scattering
7.6 Beyond the quasi-classical approximation
7.6.1 Thermo-electrics and magneto-transport
7.7 Summary
8 Non-equilibrium superconductivity
8.1 BCS-theory
8.1.1 Nambu or particle-hole space
8.1.2 Equations of motion in Nambu Keldysh space
8.1.3 Greens functions and gauge transformations
8.2 Quasi-classical Greens function theory
8.2.1 Normalization condition
8.2.2 Kinetic equation
8.2.3 Spectral densities
8.3 Trajectory Greens functions
8.4 Kinetics in a dirty superconductor
8.4.1 Kinetic equation
8.4.2 Ginzburg-Landau regime
8.5 Charge imbalance
8.6 Summary
9 Diagrammatics and generating functionals
9.1 Diagrammatics
9.1.1 Propagators and vertices
9.1.2 Amplitudes and superposition
9.1.3 Fundamental dynamic relation
9.1.4 Low order diagrams
9.2 Generating functional
9.2.1 Fhnctional differentiation
9.2.2 From diagrammatics to differential equations
9.3 Connection to operator formalism
9.4 Fermions and Grassmann variables
9.5 Generator of connected amplitudes
9.5.1 Source derivative proof
9.5.2 Combinatorial proof
9.5.3 Functional equation for the generator
9.6 One-particle irreducible vertices
9.6.1 Symmetry broken states
9.6.2 Greens functions and one-particle irreducible vertices
9.7 Diagrammatics and action
9.8 Effective action and skeleton diagrams
9.9 Summary
10 Effective action
10.1 Functional integration
10.1.1 Functional Fourier transformation
10.1.2 Gaussian integrals
10.1.3 Fermionic path integrals
10.2 Generators as functional integrals
10.2.1 Euclid versus Minkowski
10.2.2 Wicks theorem and functionals
10.3 Generators and 1PI vacuum diagrams
10.4 1PI loop expansion of the effective action
10.5 Two-particle irreducible effective action
10.5.1 The 2PI loop expansion of the effective action
10.6 Effective action approach to Bose gases
10.6.1 Dilute Bose gases
10.6.2 Effective action formalism for bosons
10.6.3 Homogeneous Bose gas
10.6.4 Renormalization of the interaction
10.6.5 Inhomogeneous Bose gas
10.6.6 Loop expansion for a trapped Bose gas
10.7 Summary
11 Disordered conductors
11.1 Localization
11.1.1 Scaling theory of localization
11.1.2 Coherent backscattering
11.2 Weak localization
11.2.1 Quantum correction to conductivity
11.2.2 Cooperon equation
11.2.3 Quantum interference and the Cooperon
11.2.4 Quantum interference in a magnetic field
……
12 Classical Statistical Dynamics
Appendices
前言/序言
The purpose of this book is to provide an introduction to the applications of quantum field theoretic methods to systems out of equilibrium. The reason for adding a book on the subject of quantum field theory is two-fold: the presentation is, to my knowledge, the first to extensively present and apply to non-equilibrium phenomena the real-time approach originally developed by Schwinger, and subsequently applied by Keldysh and others to derive transport equations. Secondly, the aim is to show the universality of the method by applying it to a broad range of phenomena. The book should thus not just be of interest to condensed matter physicists, but to physicists in general as the method is of general interest with applications ranging the whole scale from high-energy to soft condensed matter physics. The universality of the method, as testified by the range of topics covered, reveals that the language of quantum fields is the universal description of fluctuations, be they of quantum nature, thermal or classical stochastic. The book is thus intended as a contribution to unifying the languages used in separate fields of physics, providing a universal tool for describing non-equilibrium states.
Chapter 1 introduces the basic notions of quantum field theory, the bose and fermi quantum fields operating on the multi-particle state spaces. In Chapter 2, op- erators on the multi-particle space representing physical quantities of a many-body system are constructed. The detailed exposition in these two chapters is intended to ensure the book is self-contained. In Chapter 3, the quantum dynamics of a many-body system is described in terms of its quantum fields and their correla- tion functions, the Greens functions. In Chapter 4, the key formal tool to describe non-equilibrium states is introduced: Schwingers closed time path formulation of non-equilibrium quantum field theory, quantum statistical mechanics. Perturbation theory for non-equilibrium states is constructed starting from the canonical operator formalism presented in the previous chapters. In Chapter 5 we develop the real-time formalism necessary to deal with non-equilibrium states; first in terms of matrices and eventually in terms of two different types of Greens functions. The diagram representation of non-equilibrium perturbation theory is constructed in a way that the different aspects of spectral and quantum kinetic properties appear in a physi- cally transparent and important fashion for non-equilibrium states. The equivalence of the real-time and imaginary-time formalisms are discussed in detail. In Chap- ter 6 we consider the coexistence regime between equilibrium and non-equilibrium states, the linear response regime. In Chapter 7 we develop and apply the quantum kinetic equation approach to the normal state.
好的,这是一份关于《非平衡态量子场论》(Quantum Field Theory Of Non-equilibrium States)的详细图书简介,该简介着重于该领域的核心概念、历史发展、关键理论框架及其在现代物理学中的重要应用,同时避免提及您所指的特定书名及其内容。 --- 量子场论的动态前沿:非平衡态的深层探索 在理论物理学的广袤疆域中,量子场论(QFT)无疑占据着核心地位。它成功地将狭义相对论与量子力学完美结合,构建了描述基本粒子及其相互作用的精确框架。然而,传统的QFT范式,如微扰论和基于真空态的散射分析,主要集中于系统的平衡态或渐近分离的末态。这种处理方式在粒子物理对撞实验中取得了巨大成功,但在面对宇宙演化、凝聚态系统中的相变、或瞬态物理现象时,其局限性便暴露无遗。 现实世界是动态的、演化的,充满了非平衡状态。从宇宙大爆炸后的夸克-胶子等离子体的形成,到材料内部瞬态激发态的产生,再到量子信息处理中系统对外部扰动的响应,理解物质和能量在非平衡条件下的演化机制,已成为当代理论物理学亟待攻克的堡垒。 本书旨在系统性地梳理和深入探讨非平衡态量子场论这一前沿领域,为研究人员提供一个全面且严谨的理论工具箱,用以分析和解决那些超越传统平衡态假设的复杂物理问题。 第一部分:理论基础与演化框架的重塑 非平衡态研究的首要挑战在于如何有效地描述系统随时间的演化,尤其是在量子层面。本书首先奠定了必要的数学和物理基础,重点回顾了经典场论中描述时间演化的工具,并将其提升至量子场论的层面。 1. 扩展的路径积分与作用量原理: 平衡态的描述通常依赖于欧几里得作用量和维克定理。然而,在实时间演化中,我们需要一个能够直接处理时间路径的框架。本书将详尽介绍实时间路径积分(Real-Time Path Integrals)的构造,包括其在高频振荡下的处理技巧,以及如何将其推广至包含复杂的(非平庸的)经典背景场或驱动场的系统。特别地,将深入探讨Keldysh-Schwinger形式的有效作用量及其在计算系统时间演化关联函数中的核心作用。 2. 输运方程与有效场论的桥梁: 平衡态QFT往往可以转化为简单的统计力学问题。但在非平衡态下,我们需要描述粒子密度、能量流等宏观输运量。本书将聚焦于介于玻尔兹曼方程与量子场论之间的过渡区域。重点解析如何从微观的量子动力学出发,推导出适用于描述有限温度和有限密度下输运现象的量子输运方程,例如朗道-吉尔曼方程或更一般的玻尔兹曼方程的量子场论修正形式。 3. 费曼图在实时间的应用: 传统的费曼图和微扰论是基于虚时间或渐近态的。在非平衡态下,费曼图的拓扑结构和传播子(Propagators)必须进行根本性的修改。本书将详细阐述开放/闭合时间路径上的费曼图规则,解释为何单圈(one-loop)计算在实时间场景下会产生额外的、与系统演化历史相关的项,以及如何利用这些修正的图来计算响应函数和粒子产生率。 第二部分:关键理论方法与数值实现 非平衡态的精确解析解极其罕见,因此发展高效的数值和近似方法至关重要。本部分着重介绍当前最前沿的计算技术。 4. 场平均方法(Mean-Field Approaches): 在许多情况下,系统动力学可以被简化为背景场或平均场的演化。本书将介绍经典场近似(Classical Field Approximation)的应用,尤其是在宇宙学和高能重离子碰撞等高密度、弱耦合的领域。同时,将对比讨论平均场近似(Mean-Field Approximation)与更精细的随机时间演化方法的优劣。 5. 自洽演化与闭合方程: 为了在有限时间内描述非平衡动力学,研究者发展了多种闭合理论(Closed Formalisms),例如著名的一环有效作用量方案或随机时间演化方案。这些方法试图通过定义一个演化方程来描述有效场或格林函数的演化,从而避免无限的费曼图重整化。本书将对这些方案的适用范围、收敛性及其物理图像进行批判性分析。 6. 格点量子场论(Lattice QFT)的挑战与机遇: 将格点方法应用于实时间演化是一个著名的难题,主要源于“符号问题”(Sign Problem)。本书将探讨绕过或减轻符号问题的最新策略,包括使用解析延拓、重加权技术或引入虚时间截断的方法,并讨论它们在模拟量子退火或量子相变过程中非平衡启动方面的潜力。 第三部分:前沿应用与物理场景 非平衡态QFT的应用范围极其广泛,横跨高能物理、凝聚态物理乃至量子信息科学。本书的第三部分将通过具体的物理模型,展示理论框架的强大解释力。 7. 极端条件下的粒子产生: 在宇宙学暴胀时期或重离子对撞中,强场或高密度环境会导致真空的剧烈激发,产生大量的粒子对(如真空极化和拓扑激发)。本书将运用非平衡QFT工具,计算拉伸场背景下粒子的对产生率,并探讨非阿贝尔规范场在早期宇宙演化中的动力学。 8. 物质的相变与动力学重构: 许多重要的物理现象都涉及系统从一个相态快速跃迁到另一个相态的过程,例如超导体的超快激发或夸克-胶子等离子体的冷却。本书将分析这些过程中的临界动力学,讨论拓扑缺陷(如畴壁、涡旋)的形成和演化,以及拓扑保护的激发态如何响应外部驱动。 9. 量子耗散与开放系统动力学: 在凝聚态和量子光学中,系统通常并非孤立存在,而是与环境(热浴)相互作用。这引入了耗散和退相干。本书将介绍如何利用开放系统的量子场论框架(如使用林德布拉德方程的场论推广或使用对相互作用的微扰处理),来描述量子信息在具有热力学背景的系统中如何演化和弛豫。 结语 非平衡态量子场论是连接微观基本定律与宏观复杂现象之间的关键桥梁。本书的编写旨在汇集该领域中经过时间检验的理论工具与最新的研究进展,为读者提供一个清晰、深入且具有操作性的学习路径。通过掌握这些工具,理论物理学家将能更有效地探索那些瞬息万变、充满活力的量子世界。它不仅是研究高能和宇宙学现象的必备参考,也是理解复杂材料科学和量子信息系统演化的重要理论基石。