This is my personal blog, for the purpose of recording my learning progress. For every single idea which I believe is crucial for understanding specific physics or other topics, I have been trying my best to write them down. On one hand, this can help myself refreshing my mind from time to time, and on the other, if someone else loving physics happens to meet this site, I hope either these materials can help them or they can provide important advice for me to revise some key stuff, which could help improving my understanding!

We all have such moments when forgetting something we already understood before. So why not writing them down when you are sure you have got it (maybe someday, what you were sure about turns out to be wrong!)? Also, learning physics, or perhaps anything else, is a process of accumulating and we can never say what is important or not. Neither can we say with hundred percent confidence that we really understand the real meaning of some specific issues – this makes me recall a saying by R. Feynman – ‘illusion of understanding’. So let’s write everything in mind down to paper, and have a look in the future (or show around to others). There are two cases possibly to happen – one is ‘Ah ha, what I thought at that time is absolutely correct!’ and we then get a deeper impression in mind about how it works. The other case is that ‘Oh no, the stuff I wrote at that time is totally wrong!!!’. That is, however, not totally a disaster since we now realize something is going wrong, which, at least, is better than pretending everything is right!

At last, it is reading, writing, reviewing and effective interaction that makes everybody and also physics itself different from what it was yesterday. So, let’s write!