這段改篇自 2010 年 4 月 30 日的對話。
（CKY，CCK：我不覺得是那樣，因為我基本上不太懂數學。我覺得很多時候，我感到很深的題目，其他人都會覺得很淺。）
不一定是那樣。你可能有時是被騙了。
有些考生很奸詐，會用一些「不君子方法」去打擊對手。一方面，你不要用那些方法；另一方面，你不要被那些方法所傷。
有些科目，尤其是數學科，當你有很多題目都不懂做時，你很難分辨，那是因為自己的數學過差，還是因為該份試卷過深。所以，通常在試後，你都會跟其他考生比較一下。如果大部分人也覺得那份試卷不深的話，你會驚惶失措；如果大部分人也覺得那份試卷不淺的話，你會心安理得。
有些考生就會看準這一點，無論自己剛才考試時的表現如何，也會宣稱自己「覺得題目很淺」、「全部也懂做」，以打擊對手的信心，從而影響對手在往後科目的表現。
— Me@2011.02.16
2011.02.16 Wednesday (c) All rights reserved by ACHK
Spin is not related to the 3D real space wavefunction transformation.
What is the fundamental origin of spins?
Or, what is the extra dimension?
Don’t we live actually in a 3+1 D space instead of 3D?
“Rotation symmetry” in 3+1 D: Lorentz symmetry.
Wavefunctions with spins are actually the basis for the representation of rotation transformations in 3+1D.
Fundamentally, spins arises from the special relativity.
Quantum mechanics + relativity –> Relativistic quantum mechanics, or more precisely, quantum field theory (in relativity, a force has to be carried by a field to avoid instantaneous interaction.)
— Page 37, general angular momentum and spin
— 2007-08 PHY5410 Quantum Mechanics II
— Professor Renbao Liu
2011.02.16 Wednesday ACHK
Use the following algorithm:
1. Write some rubbish, at least as bad as you can.
2. Improve it a little bit, to be less rubbish.
3. Improve it a further little bit, to be less less rubbish
4. until the deadline.
— Me@2010.02.23
2011.02.16 Wednesday (c) All rights reserved by ACHK
.
The best way to come up with startup ideas is to ask yourself the question: what do you wish someone would make for you?
— Paul Graham
.
.
.
2011.02.16 Wednesday ACHK
Physics Town 