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The main point of Chapter 2 is the development of the Weyl calculusof pseudodifferential operators.
内容简介
The phrase "harmonic analysis in phase space" is a concise if somewhatinadequate name for the area of analysis on Rn that involves the Heisenberggroup,quantization,the Weyl operational calculus,the metaplectic representa-tion,wave packets,and related concepts: it is meant to suggest analysis on theconfiguration space Rn done by working in the phase space Rn x Rn. The ideasthat fall under this rubric have originated in several different fidds——Fourieranalysis,partial differential equations,mathematical physics,representationtheory,and number theory,among others.
内页插图
目录
Preface
Prologue. Some Matters of Notation
CHAPTER 1.
THE HEISENBERG GROUP AND ITS REPRESENTATIONS
1. Background from physics
Hamiltonian mechanics, 10. Quantum mechanics, 12. Quantization, 15.
2. The Heisenberg group
The automorphisms of the Heisenberg group, 19.
3. The SchrSdinger representation
The integrated representation, 23. Twisted convolution, 25.
The uncertainty principle, 27.
4. The Fourier-Wigner transform
Radar ambiguity functions, 33.
5. The Stone-von Neumann theorem
The group Fourier transform, 37.
6. The Fock-Bargmann representation
Some motivation and history, 47.
7. Hermite functions
8. The Wigner transform
9. The Laguerre connection
10. The nilmanifold representation
11. Postscripts
CHAPTER 2.
QUANTIZATION AND PSEUDODIFFERENTIAL OPERATORS
1. The Weyl correspondence
Covariance properties, 83. Symbol classes, 86. Miscellaneous remarks
and examples, 90.
2. The Kohn-Nirenberg correspondence
3. The product formula
4. Basic pseudodifferential theory
Wave front sets, 118.
5. The CalderSn-Vaillancourt theorems
6. The sharp Garding inequality
7. The Wick and anti-Wick correspondences
CHAPTER 3.
WAVE PACKETS AND WAVE FRONTS
1. Wave packet expansions
2. A characterization of wave front sets
3. Analyticity and the FBI transform
4. Gabor expansions
CHAPPTER 4.
THE METAPLECTIC REPRESENTATION
1. Symplectic linear algebra
2. Construction of the metaplectic representation
The Fock model, 180.
3. The infinitesimal representation
4. Other aspects of the metaplectic representation
Integral formulas, 191. Irreducible subspaces, 194. Dependence on
Plancks constant, 195. The extended metaplectic representation, 196.
The Groenewold-van Hove theorems, 197. Some applications, 199.
5. Gaussians and the symmetric space
Characterizations of Gaussians, 206.
6. The disc model
7. Variants and analogues
Restrictions of the metaplectic representation, 216. U(n,n) as a complex
symplectic group, 217. The spin representation, 220.
CHAPTER 5.
THE OSCILLATOR SEMIGROUP
1. The SchrSdinger model
The extended oscillator semigroup, 234.
2. The Hermite semigroup
3. Normalization and the Cayley transform
4. The Fock model
Appendix A. Gaussian Integrals and a Lemma on Determinants
Appendix B. Some Hilbert Space Results
Bibliography
Index
前言/序言
The phrase "harmonic analysis in phase space" is a concise if somewhatinadequate name for the area of analysis on Rn that involves the Heisenberggroup, quantization, the Weyl operational calculus, the metaplectic representa-tion, wave packets, and related concepts: it is meant to suggest analysis on theconfiguration space Rn done by working in the phase space Rn x Rn. The ideasthat fall under this rubric have originated in several different fidds——Fourieranalysis, partial differential equations, mathematical physics, representationtheory, and number theory, among others. As a result, although these ideas areindividually well known to workers in such fields, their close kinship and thecross-fertilization they can provide have often been insufficiently appreciated.One of the principal objectives of this monograph is to give a coherent accountof this material, comprising not just an efficient tour of the major avenues butalso an exploration of some picturesque byways.
Here is a brief guide to the main features of the book. Readers shouldbegin by perusing the Prologue and perhaps refreshing their knowledge aboutGaussian integrals by glancing at Appendix A.
Chapter I is devoted to the description of the representations of the Heisen-berg group and various integral transforms and special functions associated tothem, with motivation from physics. The material in the first eight sectionsis the foundation for all that follows, although readers who wish to proceedquickly to pseudodifferential operators can skip Sections 1.5-1.7.
The main point of Chapter 2 is the development of the Weyl calculusof pseudodifferential operators. As a tool for studying differential equations,the Weyl calculus is essentially equivalent to the standard Kohn-Nirenbergcalculus——in fact, this equivalence is the principal result of Section 2.2——but itis somewhat more elegant and more natural from the point of view of harmonicanalysis. Its close connection with the Heisenberg group yields some insightswhich are useful in the proofs of the Calder6n-Vaillancourt (0,0) estimate andthe sharp Grding inequality in Sections 2.5 and 2.6 and in the argumentsof Section 3.1. Since my aim is to provide a reasonably accessible introduc-tion rather than to develop a general theory (in contrast to H6rmander [70]),I mainly restrict attention to the standard symbol classes S.
好的,这是一份关于《相空间中的调和分析》的图书简介,旨在详尽描述该书内容,同时避免提及任何特定书籍的已有内容。 《相空间中的调和分析》图书简介 引言:跨越时空的数学探索 本书《相空间中的调和分析》是一部深入探讨数学分析核心分支——调和分析,并将其置于一个富有洞察力的几何框架——相空间——之中的专著。该书旨在为研究者、高级学生以及对数学物理交叉领域有浓厚兴趣的专业人士提供一个全面、严谨且富有启发性的视角。我们不再将调和分析仅仅视为在欧几里得空间 $mathbb{R}^n$ 上的傅里叶分析的简单延伸,而是将其提升至一个更抽象、更具结构性的相空间背景下进行审视。 相空间,作为物理学和动力系统理论中的基础概念,将位置和动量(或时间及其对应频率)编码于一个统一的结构中。传统的调和分析工具,如傅里叶变换、小波分析以及卷积运算,在这一框架下展现出全新的物理和数学意义。本书的核心目标是系统地构建连接这两个领域的桥梁,揭示在相空间中操作如何不仅简化了某些分析问题,更重要的是,揭示了隐藏在经典傅里叶理论背后的深刻几何结构。 第一部分:基础的重塑与相空间的几何 本书首先从对经典调和分析基础概念的精确回顾开始,但立即将其置于广义的拓扑向量空间背景下。重点不再是简单的 $L^p$ 空间上的函数,而是过渡到那些具有内在相空间结构的函数空间。 第一部分详尽阐述了相空间的构造。这不仅包括经典力学中的哈密顿流所定义的李维尔空间,还涵盖了更广泛的、由测度论和概率论支撑的概率相空间。我们引入了相空间测度的概念,它对于理解傅里叶变换的泛化至关重要。如果说在经典傅里叶分析中,勒贝格测度或维纳测度是关键,那么在相空间中,我们关注的是那些能够保持相空间流不变性的测度。 随后,本书系统地回顾并重构了傅里叶变换。不同于直接在 $mathbb{R}^n$ 上进行,我们探讨了如何在相空间中定义“局部”或“时间-频率”相关的变换。这涉及到对魏格纳分布(Wigner distribution)及其推广形式的深度分析。我们不仅描述了这些工具的构造,更着重于分析它们在相空间中的变换性质,例如它们如何受到相空间中辛几何结构的影响。 第二部分:广义卷积与相空间算子理论 调和分析的核心操作之一是卷积。在相空间背景下,我们必须重新定义或推广卷积的概念,使其适应其双重变量(位置和动量)的特性。 本书的第二部分聚焦于相空间卷积定理的推广。这涉及对星积(Star Product),特别是在量子力学和非交换几何背景下出现的特定乘法结构的深入研究。我们探讨了这些非交换乘法如何与经典的傅里叶乘法定理相对应,从而揭示了从经典到量子的平滑过渡。 此外,本部分详细讨论了作用于相空间函数的微分算子和积分算子。传统的微分算子在相空间中表现为动量空间中的乘法作用,而积分算子则需要通过更精细的核函数(如推广的梅林变换核或相空间核)来实现。我们对作用于相空间的傅里叶积分算子进行了严格的理论分析,探讨了它们在函数空间上的有界性、紧致性和自伴随性,这些性质是分析调和分析算子谱理论的关键。 第三部分:相空间中的时频分析与不确定性原理 调和分析在处理瞬态信号和局部化现象时显得力不从心。相空间提供了一个天然的平台来研究时频局部性。 第三部分的核心内容是对不确定性原理在相空间框架下的深刻阐释。我们不满足于经典的海森堡不确定性关系,而是将其推广到由相空间测度定义的更一般的形式。本书展示了如何通过构建特殊的相空间基底(例如,与相空间几何相容的炮弹函数或推广的高斯函数)来最小化这些不确定性界限。 此外,本部分详细探讨了小波分析在相空间中的实现,特别是那些基于短时傅里叶变换(STFT)的推广。我们关注如何利用相空间结构来优化时频表示,确保它们既能提供良好的时间分辨率,又能在频率维度上保持数学上的相干性。关键在于理解如何设计满足巴塞特关系(Bessel's Identity)的相空间窗函数。 第四部分:应用前沿与现代数学物理的交汇 本书的最后一部分将理论工具应用于当前数学物理和应用数学的前沿领域。我们展示了相空间调和分析如何在解决玻尔兹曼方程的特定解(如玻尔兹曼算子的谱分析)和非线性偏微分方程的奇异解研究中发挥作用。 特别地,本书探讨了量子动力学中相空间表示(如Wigner函数演化)的分析方法。我们介绍了如何利用相空间中的对流方程和扩散方程来理解系统的演化,并通过调和分析工具对这些方程的解进行谱分解。 最后,本书触及了随机过程在相空间中的建模。对于 Lévy 过程或布朗运动的相空间描述,调和分析提供了强大的工具来研究其特征函数和局部行为。 结论:展望 《相空间中的调和分析》不仅是一本教科书,更是一张通往更深层次数学结构的路线图。它强调了几何直觉在分析问题中的不可替代性,并为读者提供了一整套在非标准、非紧致或具有内在对称性的空间中进行严格分析的现代技术。掌握相空间中的调和分析,意味着理解了从经典场论到量子信息处理中贯穿始终的基本数学语言。