Today I stayed at my room to study and work on Problems sets for Physics 211. It was very very inefficient day, I only read 2/3 of a chapter of Mukhanov's book ( it's really short chapter... and chapter 1 !!!), and not even solved a single sub problem of problem 1. Actually 1-(b) I'm working on should not be that difficult, showing equivalence of two commutation relationships. But showing it generally with very abbreviated notations are confusing me so much. I though I figured it out right before dinner (after working on it more than 6 hours) but I figured out that there's some flaw. I am pretty sure I am mixing the index of different mode and different oscillators..... in this case working with continuous field would be more easier, in terms of notations......

I gave up doing the p-sets. I should start working on it tomorrow with fresh mind. I should read Georgi's book and more on Mukhanov's to do other problems in Physics 211 HW.

I really should drop differential topology. I'm pretty sad since I could learn a lot in that class. But I think physics 211 is more important than that.