Book contents
- Frontmatter
- Contents
- Preface
- 1 A brief review of quantum mechanics
- 2 Single-particle states
- 3 Second quantization
- 4 The electron gas
- 5 A brief review of statistical mechanics
- 6 Real-time Green's and correlation functions
- 7 Applications of real-time Green's functions
- 8 Imaginary-time Green's and correlation functions
- 9 Diagrammatic techniques
- 10 Electron gas: a diagrammatic approach
- 11 Phonons, photons, and electrons
- 12 Superconductivity
- 13 Nonequilibrium Green's function
- Appendix A Second quantized form of operators
- Appendix B Completing the proof of Dzyaloshinski's rules
- Appendix C Lattice vibrations in three dimensions
- Appendix D Electron-phonon interaction in polar crystals
- References
- Index
1 - A brief review of quantum mechanics
Published online by Cambridge University Press: 05 April 2013
- Frontmatter
- Contents
- Preface
- 1 A brief review of quantum mechanics
- 2 Single-particle states
- 3 Second quantization
- 4 The electron gas
- 5 A brief review of statistical mechanics
- 6 Real-time Green's and correlation functions
- 7 Applications of real-time Green's functions
- 8 Imaginary-time Green's and correlation functions
- 9 Diagrammatic techniques
- 10 Electron gas: a diagrammatic approach
- 11 Phonons, photons, and electrons
- 12 Superconductivity
- 13 Nonequilibrium Green's function
- Appendix A Second quantized form of operators
- Appendix B Completing the proof of Dzyaloshinski's rules
- Appendix C Lattice vibrations in three dimensions
- Appendix D Electron-phonon interaction in polar crystals
- References
- Index
Summary
Come forth into the light of things, Let nature be your teacher.
William Wordsworth, The Tables TurnedThe main focus of this book is many-particle systems such as electrons in a crystal. Such systems are studied within the framework of quantum mechanics, with which the reader is assumed to be familiar. Nevertheless, a brief review of this subject will provide an opportunity to establish notation and collect results that will be used later on.
The postulates
Quantummechanics is based on five postulates, listed below with some explanatory comments.
The quantum state
The quantum state of a particle, at time t, is described by a continuous, singlevalued, square-integrable wave function Ψ(r, t), where r is the position of the particle. In Dirac notation, the state is represented by a state vector, or ket, ∣Ψ(t)⟩, which is an element of a vector space V. We define a dual vector space V* whose elements, called bras, are in one-to-one correspondence with the elements of V: ket ∣α⟩ ∈ V ⟷ bra ⟨α∣ ∈ V*, as illustrated in Figure 1.1. The bra corresponding to ket c∣α⟩ is c* ⟨∣, where c*. is the complex conjugate of c. The inner product of kets ∣α⟩ and ∣β⟩ is denoted by ⟨β∣α⟩, and it is a complex number (c-number). Note that the inner product is obtained by combining a bra and a ket. By definition, ⟨β∣α⟩ = ⟨α∣β⟩*.
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- Publisher: Cambridge University PressPrint publication year: 2013