Halcyon Days 2
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There were so many creative things happening back then with computer games. Almost every new game that came out was a new way of slicing up the universe.
— Marc Goodman
– Halcyon Days (book)
– James Hague
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2011.02.17 Thursday ACHK
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
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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
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2011.02.16 Wednesday ACHK
「狹義相對論」會教你如何運算，把你的「一格」翻譯成我的「一格」。
「狹義相對論」關心的另一個主要問題是，眾多個體因果鏈如何互相影響呢？
其中一個核心結論是，任何兩個個體的相互因果影響（causal influence），速度不會高於光速。任何兩條個體因果鏈之間的訊息傳遞（signal transmission），速度最高只能達到光速。
— Me@2011.02.15
2011.02.15 Tuesday (c) All rights reserved by ACHK
In 1954, Chen Ning Yang and Robert Mills proposed to generalize these ideas to noncommutative groups. A noncommutative gauge group can describe a field that, unlike the electromagnetic field, interacts with itself. For example, general relativity states that gravitational fields have energy, and special relativity concludes that energy is equivalent to mass. Hence a gravitational field induces a further gravitational field. The nuclear forces also have this self-interacting property.
— Wikipedia on Introduction to gauge theory
2011.02.15 Tuesday ACHK
有一個簡單的方法，可以知道程式作者有沒有為程式用者設想：
看看安裝一個程式時，該個程式會不會要求你「重新開機」。
「好程式」和「壞程式」的分別是，
安裝「好程式」時，它不會要求你「重新開機」。
結論是，大部分情況下，不應安裝任何會要求你「重新開機」的程式。
— Me@2011.02.13
2011.02.15 Tuesday (c) All rights reserved by ACHK
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You can choose whatever name you like for the two types of government. I personally call the type of government which can be removed without violence “democracy”, and the other “tyranny”.
— Karl Popper
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2011.02.15 Tuesday ACHK
這段改篇自 2010 年 4 月 30 日的對話。
當校內考試的題目異於常態時，你毋須擔心，因為只有公開試的成績，才對你的前途有決定性的影響。當公開試的題目異於常態時，你亦毋須擔心，因為「公開試」是公開的，有大量的參賽者。有奇怪題目時，不只是你要面對，而是其他大量的考生，也會遭遇同樣的困境。整體的效果是，「奇怪題目」對你的成績等級，不會有明顯的影響。
（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。
— Me@2011.02.14
2011.02.14 Monday (c) All rights reserved by ACHK
Spin is a consequence of Relativity.
— Richard P. Feynman
2011.02.14 Monday ACHK
Be ahead of your own time.
Back from the future.
— Me@2010.10.13
2011.02.14 Monday (c) All rights reserved by ACHK
James Cole: I am insane. And you are my insanity.
— Twelve Monkeys
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2011.02.14 Monday ACHK
但是，「客觀時間」不只是由一條因果鏈，而是由無數個體的各自因果鏈所組成。要把眾多因果鏈合體，就要把它們「同步化」，從而形成一個「因果網絡」。這個「因果網絡」，就是宇宙的「客觀時間」。
那樣，我的「因果鏈」和你的「因果鏈」會不會有偏差呢？
有時候會。有些時候，我因果鏈的「一格」，不等如你因果鏈的「一格」。這個就是愛因斯坦的「狹義相對論」所要處理的問題。「狹義相對論」會教你如何運算，把你的「一格」翻譯成我的「一格」。
— Me@2011.02.13
2011.02.13 Sunday (c) All rights reserved by ACHK
Identical particles 2
Surprisingly, gauge symmetry can give a deeper explanation for the existence of interactions, such as the electrical and nuclear interactions. This arises from a type of gauge symmetry relating to the fact that all particles of a given type are experimentally indistinguishable from one other.
— Wikipedia on Introduction to gauge theory
2011.02.13 Sunday ACHK
超世 3
樹要往高往上往光輝處生，根要往下往深往黑暗處長。
— 改篇自尼采
A man does not show his greatness by being at one extremity, but rather by touching both at once.
— Blaise Pascal
越能入世的人越能出世；越能出世的人越能入世。
— Me@2011.02.08
2011.02.13 Sunday (c) All rights reserved by ACHK
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Ultimately, you have to decide which is more important — building your own brand, or building the brand of the website you’re contributing to? While these two concepts are not necessarily opposed, I strongly urge everyone reading this to err on the side of building your own brand whenever possible. Websites tend to come and go; the only sensible long term strategy is to invest in something that’s guaranteed to be around for the rest of your life: you.
— Are You a Digital Sharecropper?
— programming and human factors
— by Jeff Atwood
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2011.02.13 Sunday ACHK
這段改篇自 2010 年 4 月 30 日的對話。
「1.36 分鐘」不是很難思考嗎？例如，某一題的分數是 4 分，對應的時間是多少分鐘？
如果用「1.36 分鐘 / 分」的話，你不能馬上知道答案。考試的時間非常緊密，不應製造任何令自己分神的事情。還有，當正式的時間分配是「1.36 分鐘 / 分」，而你卻用「1 分鐘 / 分」來盤算計劃的話，你就不知不覺地儲存了很多後備時間。
再者，我是假設了你每一題也要百分百完成，才會用總分 110 來做分母：
150 分鐘 / 110 分 = 1.36 分鐘 / 分
我是假設了你企圖要奪取全部分數，才會用那麼吝嗇，每一分只容許 1 分鐘。但是，如果你的目標只是「坐 C 望 B」的話，正如我剛才所講，你只要完成 section A 的全部和 section B 每題的 a, b 部分就可以。那樣，你運算時慢一點也可以。又或者，你可以堅持每一分只容許 1 分鐘，從而留下大量的時間，來做驗證校對的工作。
— Me@2011.02.12
2011.02.12 Saturday (c) All rights reserved by ACHK
In that instant, I realized how easy it is to give a little bit of yourself every day.
You may never know how much each gesture may mean to someone else.
— Chicken soup for the college soul
— Me@2010.11.01
2011.02.09 Wednesday ACHK
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I thought it would be useful if I explained what a nerd was. What I came up with was: someone who doesn’t expend any effort on marketing himself.
A nerd, in other words, is someone who concentrates on substance. So what’s the connection between nerds and technology? Roughly that you can’t fool mother nature. In technical matters, you have to get the right answers.
— Paul Graham
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2011.02.09 Wednesday ACHK
Physics Town 
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