内容简介
       I have tried to make the subject as accessible to beginners as possible. There are three main aspects to my approach. Logical development of the basic concepts. This is, of course, very different from the historical development of quantum field theory, which, like the historical development of most worthwhile subjects, was filled with inspired guesses and brilliant extrapolations of sometimes fuzzy ideas, as well as its fair share of mistakes, misconceptions, and dead ends. None of that is in this book. From this book, you will (I hope) get the impression that the whole subject is effortlessly clear and obvious, with one step following the next like sunshine after refreshing rain.     
作者简介
   作者:(美国)思雷德尼奇(MarkSrednicki)     
内页插图
          目录
   Preface for students
Preface for instructors
Acknowledgments
Part I Spin Zero
1 Attempts at relativistic quantum mechanics
2 Lorentz invariance (prerequisite: 1)
3 Canonical quantization of scalar fields (2)
4 The spin-statistics theorem (3)
5 The LSZ reduction formula (3)
6 Path integrals in quantum mechanics
7 The path integral for the harmonic oscillator (6)
8 The path integral for free field theory (3, 7)
9 The path integral for interacting field theory (8)
10 Scattering amplitudes and the Feynman rules (5, 9)
11 Cross sections and decay rates (10)
12 Dimensional analysis with h = c = i (3)
13 The Lehmann-Kallen form of the exact propagator (9)
14 Loop corrections to the propagator (10, 12, 13)
15 The one-loop correction in Lehmann-Kallen form (14)
16 Loop corrections to the vertex (14)
17 Other 1PI vertices (16)
18 Higher-order corrections and renormalizability (17)
19 Perturbation theory to all orders (18)
20 Two-particle elastic scattering at one loop (19)
21 The quantum action (19)
22 Continuous symmetries and conserved currents (8)
23 Discrete symmetries: P, T, C, and Z (22)
24 Nonabelian symmetries (22)
25 Unstable particles and resonances (14)
26 Infrared divergences (20)
27 Other renormalization schemes (26)
28 The renormalization group (27)
29 Effective field theory (28)
30 Spontaneous symmetry breaking (21)
31 Broken symmetry and loop corrections (30)
32 Spontaneous breaking of continuous symmetries (22, 30)
Part II Spin One Half
33 Representations of the Lorentz group (2)
34 Left- and right-handed spinor fields (3, 33)
35 Manipulating spinor indices (34)
36 Lagrangians for spinor fields (22, 35)
37 Canonical quantization of spinor fields I (36)
38 Spinor technology (37)
39 Canonical quantization of spinor fields II (38)
40 Parity, time reversal, and charge conjugation (23, 39)
41 LSZ reduction for spin-one-half particles (5, 39)
42 The free fermion propagator (39)
43 The path integral for fermion fields (9, 42)
44 Formal development of fermionic path integrals (43)
45 The Feynman rules for Dirac fields (10, 12, 41, 43)
46 Spin sums (45)
47 Gamma matrix technology (36)
48 Spin-averaged cross sections (46, 47)
49 The Feynman rules for Majorana fields (45)
50 Massless particles and spinor helicity (48)
51 Loop corrections in Yukawa theory (19, 40, 48)
52 Beta functions in Yukawa theory (28, 51)
53 Functional determinants (44, 45)
Part III Spin One
54 Maxwells equations (3)
55 Electrodynamics in Coulomb gauge (54)
56 LSZ reduction for photons (5, 55)
57 The path integral for photons (8, 56)
58 Spinor electrodynamics (45, 57)
59 Scattering in spinor electrodynamics (48, 58)
60 Spinor helicity for spinor electrodynamics (50, 59)
61 Scalar electrodynamics (58)
62 Loop corrections in spinor electrodynamics (51, 59)
63 The vertex function in spinor electrodyna, mics (62)
64 The magnetic moment of the electron (63)
65 Loop corrections in scalar electrodynamics (61, 62)
66 Beta functions in quantum electrodynamics (52, 62)
67 Ward identities in quantum electrodynamics I (22, 59)
68 Ward identities in quantum electrodynamics II (63, 67)
69 Nonabelian gauge theory (24, 58)
70 Group representations (69)
71 The path integral for nonabelian gauge theory (53, 69)
72 The Feynman rules for nonabelian gauge theory (71)
73 The beta function in nonabelian gauge theory (70, 72)
74 BRST symmetry (70, 71)
75 Chiral gauge theories and anomalies (70, 72)
76 Anomalies in global symmetries (75)
77 Anomalies and the path integral for fermions (76)
78 Background field gauge (73)
79 Gervais-Neveu gauge (78)
80 The Feynman rules for N x N matrix fields (10)
81 Scattering in quantum chromodynamics (60, 79, 80)
82 Wilson loops, lattice theory, and confinement (29, 73)
83 Chiral symmetry breaking (76, 82)
84 Spontaneous breaking of gauge symmetries (32, 70)
85 Spontaneously broken abelian gauge theory (61, 84)
86 Spontaneously broken nonabelian gauge theory (85)
87 The Standard Model: gauge and Higgs sector (84)
88 The Standard Model: lepton sector (75, 87)
89 The Standard Model: quark sector (88)
90 Electroweak interactions of hadrons (83, 89)
91 Neutrino masses (89)
92 Solitons and monopoles (84)
93 Instantons and theta vacua (92)
94 Quarks and theta vacua (77, 83, 93)
95 Supersymmetry (69)
96 The Minimal Supersymmetric Standard Model (89, 95)
97 Grand unification (89)
Bibliography
Index      
前言/序言
     Quantum field theory is the basic mathematical language that is used to describe and analyze the physics of elementary particles. The goal of this book is to provide a concise, step-by-step introduction to this subject, one that covers all the key concepts that are needed to understand the Standard Model of elementary particles, and some of its proposed extensions.
  In order to be prepared to undertake the study of quantum field theory, you should recognize and understand the following equations:
  This list is not, of course, complete; but if you are familiar with these equations, you probably know enough about quantum mechanics, classical mechanics, special relativity, and electromagnetism to tackle the material in this book.
  Quantum field theory has the reputation of being a subject that is hard to learn. The problem, I think, is not so much that its basic ingredients are unusually difficult to master (indeed, the conceptual shift needed to go from quantum mechanics to quantum field theory is not nearly as severe as the one needed to go from classical mechanics to quantum mechanics), but rather that there are a lot of these ingredients. Some are fundamental, but many are just technical aspects of an unfamiliar form of perturbation theory.
  In this book, I have tried to make the subject as accessible to beginners as possible. There are three main aspects to my approach.
  Logical development of the basic concepts. This is, of course, very different from the historical development of quantum field theory, which, like the historical development of most worthwhile subjects, was filled with inspired guesses and brilliant extrapolations of sometimes fuzzy ideas, as well as its fair share of mistakes, misconceptions, and dead ends. None of that is in this book. From this book, you will (I hope) get the impression that the whole subject is effortlessly clear and obvious, with one step following the next like sunshine after refreshing rain.
  Illustration of the basic concepts with the simplest examples. In most fields of human endeavor, newcomers are not expected to do the most demanding tasks right away. It takes time, dedication, and lots of practice to work up to what the accomplished masters are doing. There is no reason to expect quantum field theory to be any different in this regard. Therefore, we will start off by analyzing quantum field theories that are not immediately applicable to the real world of electrons, photons, protons, etc., but that will allow us to gain familiarity with the tools we will need, and to practice using them. Then, when we do work up to "real physics," we will be fully ready for the task. To this end, the book is divided into three parts: Spin Zero, Spin One Half, and Spin One. The technical complexities associated with a particular type of particle increase with its spin. We will therefore first learn all we can about spinless particles before moving on to the more difficult (and more interesting) nonzero spins. Once we get to them, we will do a good variety of calculations in (and beyond) the Standard Model of elementary particles.    
				
 
				
				
					宏伟的叙事:一个关于时间、空间与存在的探索  这是一部关于时间本质、空间结构及其在宇宙演化中扮演角色的深刻哲学与物理学探索的著作。它摒弃了对微观粒子相互作用的直接描述,转而聚焦于一个宏大的、包罗万象的视角:即我们所感知的现实,是如何从更基本、更抽象的结构中涌现出来的。  本书的叙事始于对时间流逝的形而上学审视。作者质疑了我们对“过去”、“现在”和“未来的”直观理解,深入探讨了时间的单向性(箭头问题)在物理学定律的对称性面前所面临的悖论。它不是关于如何计算特定粒子的衰变率,而是关于“为什么存在时间?”以及“如果时间是一种涌现现象,那么它的基本构件是什么?”  在探讨了时间的维度之后,焦点转向了空间的拓扑与几何的深层奥秘。本书细致地描绘了从欧几里得几何到非欧几何的演变,但更进一步,它探索了空间本身是否是连续的,抑或是由某种离散的、不可再分的“量子块”构筑而成。我们将跟随作者的思绪,考察黎曼几何如何为描述引力的场奠定基础,以及这种几何结构如何决定了物质在其中运动的轨迹。  全书的核心论点在于“关联性”与“信息”作为宇宙的基本实体的地位。作者认为,在任何描述具体粒子或场的理论之下,存在着一种更深层次的、关于信息如何被编码和传递的网络。这种网络决定了物理定律的边界条件。   第一部分:时间的炼金术——从熵到存在  章节一:时间的幻象与实在 本章首先解构了牛顿式的绝对时间概念。它深入分析了热力学第二定律——熵增——如何与微观物理定律的时间可逆性形成鲜明对比。作者提出,时间的箭头可能并非源于能量的耗散,而是源于宇宙初始条件的极端低熵状态,以及系统在多重可能性中“选择”特定路径的必然性。我们将探讨“块状宇宙”模型(Block Universe),并评估它对自由意志概念的挑战。  章节二:记忆、因果与时间旅行的逻辑陷阱 本节转向逻辑与因果链的哲学分析。它不讨论特定的时空弯曲度,而是探究在什么逻辑结构下,因果律能够保持其意义。通过考察著名的祖父悖论,作者试图界定哪些时空结构是“自我一致的”(self-consistent),哪些是逻辑上禁锢的。这部分更像是一场关于逻辑本体论的辩论,而非对广义相对论精确解的求解。  章节三:潜能与实现:时间的涌现模型 本章提出了一个大胆的假设:时间并非一个背景维度,而是系统内部复杂关联状态演化的度量。它关注的是系统状态从“未确定”到“已确定”的转变过程,以及这个转变如何构成了我们对“经历”的感知。这部分深入讨论了概率论与实在感之间的桥梁。   第二部分:空间的拓扑与结构的疆界  章节四:超越维度的几何学 本书的第二部分将读者的目光从时间转向了空间。本章详细阐述了高维几何的魅力与局限性。它不涉及对特定场方程的求解,而是关注空间拓扑(Topology)如何定义了可观测的物理特性。例如,一个具有非平凡拓扑(如环面或球面)的空间,其物理性质与欧几里得平直空间有何根本区别?作者探讨了“连通性”在定义物理边界时的重要性。  章节五:场的边界条件与空间的“皮肤” “场”的概念在这里被重新定义,它不再是描述力的传递媒介,而是空间结构本身内在的属性。本章着重于空间界面的性质——即边界条件对整个物理系统的决定性影响。想象一个封闭的盒子,其边界的性质决定了内部能量的可能分布;在宏观尺度上,宇宙的边界或其“边缘”的概念如何影响了我们观测到的局部物理定律?  章节六:离散性与连续性的二元对立 本章对比了两种关于空间本质的基本观点:连续性与离散性。如果空间是连续的,那么可以无限分割;如果它是离散的,那么存在一个最小的长度单位。作者通过考察理论物理中处理无限大的方法,论证了离散化在处理基础结构问题上的潜在优势,并探讨了这种离散性可能带来的非线性效应。   第三部分:信息、关联与实在的构造  章节七:网络的实在观:从节点到结构 本书的收尾部分将时间与空间整合到一个统一的“关联网络”框架中。这里的“信息”是描述相互关系的度量,而不是传统意义上的比特或熵。作者描绘了一个由相互依赖的事件和位置构成的巨大图谱,并提出物理定律是这个图谱的最稳定的、自洽的结构表征。  章节八:熵减的动力学:组织与复杂性的起源 如果宇宙趋向于最大熵,那么复杂结构(如恒星、行星,乃至生命)的出现如何解释?本章探讨了耗散结构理论的思想,但将其提升到更基础的层面:复杂性是特定信息网络在维持其内部关联性时的一种必然副产品。这里的焦点是“组织如何抵御随机性”,而不是具体的化学反应路径。  章节九:宇宙的整体性与可还原性之辩 最后,作者提出了一个关于整体观与还原论的深刻反思。我们能否从最基本的空间-时间单元中重建我们所见的宏大宇宙?或者说,宇宙的某些特性——如意识、意义——是否只能在整体结构中被理解,而无法通过分解其组成部分来把握?本书以对物理学边界的反思作结,邀请读者思考我们对“存在”的理解,是否已经触及了最终的基石。  --- 本书的读者对象是那些对物理学基本原理抱有深刻哲学好奇心的读者,他们渴望理解支撑我们现实结构背后的终极逻辑,而非仅满足于应用特定数学工具解决可量化问题的物理学家或工程师。这是一次关于存在之维的宏大漫游。