shortened menu of courses:
1. Introduction to Condensed Matter; Einstein Model of Vibrations in Solids
2. Debye Model of Vibrations in Solids; Drude Theory of Electrons in Metals
3. Drude Theory of Electrons in Metals Sommerfeld Free Electron Theory of Electrons in Metals
4. Sommerfeld Free Electron Theory of Electrons in Metals
5. Chemistry in a Nutshell
6. Microscopic View of Vibrations in Solids in One Dimension I The Monatomic Harmonic Chain
7. Microscopic View of Vibrations in Solids in One Dimension II The Diatomic Alternating Harmonic Chain
8. Microscopic View of Electrons in Solids in One Dimension Tight Binding Chain
9. Geometry of Solids I Crystal Structure in Real Space
10. Geometry of Solids II Real Space And Reciprocal Space 2
11. Reciprocal Space and Scattering
12. Scattering Experiments II
13. Scattering Experiments III
14. Waves in Reciprocal Space
15. Nearly Free Electron Model
16. Band Structure and Optical Properties of Solids
17. Dynamics of Electrons in Bands
18. Semiconductor Devices and Introduction to Magnetism
19. Magnetic Properties of Atoms
20. Collective Magnetism
21. Mean Field Theory and Closing Thoughts

bilibili resources

B站视频

BV1QW411u736

youtube的实时字幕比较方便

https://www.youtube.com/watch?v=XQk25fSJkL8&list=PLaNkJORnlhZnC6E3z1-i7WERkferhQDzq

教授主页（这里可以看到其它课程）

http://www-thphys.physics.ox.ac.uk/people/SteveSimon/

2014course page

http://www-thphys.physics.ox.ac.uk/people/SteveSimon/condmat2014/condmat.html

2012版lecture note

http://www-thphys.physics.ox.ac.uk/people/SteveSimon/condmat2012/LectureNotes2012.pdf

小程序

http://www-thphys.physics.ox.ac.uk/people/SteveSimon/condmat2014/GlazerPrograms.html

up主传的网盘，包含软件

https://pan.baidu.com/s/16NbXSq771Y1zms0Vmaql4Q 密码：2ebb

01 Introduction to Condensed Matter; Einstein Model of Vibrations in Solids

resources

book
- 《The Oxford Solid State Basics》，可于PDFDRIVE获取
- PDFDRIVE还可找到**The Oxford Solid State Basics, Solution Manual**
webpage
- find the draft 85% similar to the 25 pounds book!
- sample exams, sample solution…
- slides & videos
message board
- 似乎停用了。希望国内学校也用这种message board，发展起来简直不要太方便

condensed matter physics

what is condensed matter physics
- 1/3 of physics
why study it?
- it is the world
- it is useful
- it is deep
  - deep ideas come out of condensed matter physics and go into other fields. ;D
- anti reductionism
- it is a laboratory for quantum and step back
  - extension of quantum mechanics and statistical mechanics

SOLID STATE

basic to more complicated fluid or super fluid, other condensed matter.

heat capacity (of solids)
- C=dQ/dT Q: heat T: capacity
- In solid, 可以认为 $C_P=C_V=C$
  - $C_P-C_V=\frac{VT \alpha^2}{\beta}$
    - $\alpha$: thermal extension coefficient，热膨胀系数
    - $\beta$: isothermal compressibility，等温压缩系数
    - solid: $\alpha$ 很小，$C_P-C_V$可忽略
monatomic moneth
- gas
  - $C_{V/N}=\frac{3}{2}k_B$
- solids
  - $C_{N}=3k_B$
  - Law of Dulong-Petit, 1819
  - we know it’s right. But why?
- Boltzmann
  - statistical mechanics to reason this question
  - Model of solid,1896
    - 原子位于谐振势阱(bottom of the harmonic)的底端，可来回振荡。biu~~biu~~
    - 温度越高，越能振荡（自由度越高），可储存的能量越高。
  - equipartition thm均分定理
    - each degree of freedom, you get 1/2 $k_B$ of heat capacity.
    - monatomic gas:
      - $p_x, p_y, p_z$ —— $C_{V/N}=\frac{3}{2}k_B$ （3个自由度）
    - solid:
      - $p_x, p_y, p_z,x, y, z$ —— $C_{N}=3k_B$ （6个自由度，三方向动能+自身坐标）
    - Law of D-P
      - Not always true
      - $T<<T_{room}$ $C_{N}<<3k_B$
      - DIAMOND:
        
        $C_{N}<<3k_B$ at $T_{room}$
      - why ？
- Einstein model of solid, 1909
  - = Boltzmann’s solid+quantum
  - $\omega=\sqrt{\frac{k}{m}}$
    - k: spring constant弹簧常数
  - 一维谐振子：
    - $E_n=h\omega(n+1/2)$
    - 求单个原子的热容
      - 配分函数$Z=\sum_{n≥0}e^{-\beta E_n}$
        
        $\beta=\frac{1}{k_BT}$
      - 对Z求导，能量期望值:
        
        $= - \frac{1}{Z}\frac{\partial Z}{\partial \beta}=h\omega(n_B(\beta h\omega)+1/2)$
        
        玻色因子$n_B=\frac{1}{e^{\beta h \omega}-1}$
      - 计算热容
        $$ C=\frac{\partial }{\partial T}= k_B(\beta h \omega)^2 \frac{e^{\beta h \omega}}{(e^{\beta h \omega}-1)^2} $$
      - 注：此热容为一维谐振单原子之热容。
    - 在三维振荡，结果乘3：
      
      $$ C_{/N}=3k_B(\beta h \omega)^2 \frac{e^{\beta h \omega}}{(e^{\beta h\omega}-1)^2} $$
      - 高温极限：
        
        $$ k_BT>>h\omega \space\space-> \beta h\omega<<1\e^{\beta h\omega}\approx 1+\beta h\omega+… $$
        
        $$ C_{/N}=3k_B $$
        
        高温下量子系统趋近于经典系统，量子统计退化到玻尔兹曼经典统计。
      - 低温极限：
      $$ k_BT<<h\omega \space\space ->e^{\beta h\omega}\space is\space big! $$
      
      $$ C_{/N}=3k_B(\beta h\omega)^2e^{-\beta h\omega} $$
      - 低温时，C随T急速下降
  - diamond ?
    - $\omega=\sqrt{\frac{k}{m}}$ : Einstein frenquency
      - 大部份材料的$h\omega$比较小
      - diamond: carbon, thus m small; tough, thus k big, so it’s $\omega$ is really big
      - shortage: data is wrong?
        
        实测数据下降得没有那么快
      - 低温，most materials(including diamond), $C \approx T^3$
        
        exception: metal(copper) $C=\alpha T^3+ \gamma T$
        
        but no C as low as E’s prediction
    - Debye model
    - collective solid vibration motion
      - sound wave

02 Debye Model of Vibrations in Solids; Drude Theory of Electrons in Metals

review

Boltzmann
- $C_{/N}=3k_B$
Einstein
- quantum
- C drops at low T (expected)
experiment
- $C\approx T^3$
Debye, 1912
- 爱因斯坦模型假设固体中各个原子的振动相互独立，所有的原子都具有同一频率。
- Debye的想法是，不能单独地考虑每个原子的势阱。因为一个原子振动会被弹回，但也撞击了附近原子，引起连锁振动，也就是波。
- vibration=wave(sound)
  - 波在固体中的传播通常为声学波。
- quantize sound wave like light
  - 波可以被量子化。

Einstein’s model:

= h\omega(n_B(\beta h\omega)+1/2) $$ Debye: $$ _{total} = \sum_{modes}h\omega_{modes}(n_B(\beta h\omega)_{modes}+1/2) $$ 爱因斯坦模型：温度低于谐振子的频率时，热容会降低。迪拜：盒子中分布着各个频率的谐振子，因此温度降低的时候，总有一些频率较低的谐振子能够得到激发，导致热容不会迅速呈指数形式下降。

LIGHT vs SOUND - LIGHT - 2 polarizations，2种偏振 - Longitudinal wave纵波，传播方向=振动方向 - transverse wave横波，传播方向⊥振动方向 - sound - 3 pols ASSUME: - $v_{sound}$ INDEP of POL - actually 横波比纵波慢 - v_{sound} INDEP of direction - actually

如何统计盒子内的波模数(counting waves modes in box)： - 1D box - length l - …