Recent content by luxiaolei

Hi,all, I m an undergrades and I am suffering on understanding the different representation transformations, namely from Schrödinger picture to interaction picture tupically, my lecturer didn't state which representation he was using and I m so confused, any helps would be great. Shall I bring...

Hi all. I m stucked on the question followed, any helps will be greatly appreciated. A perturbation has the form H'=z act on a two level system which they have different parity. So the first order correction to the energy level 1 and 2 are give by: E11=<ψ1| H' |ψ1> Same for level 2...

Thank you so much!

Hi all, I must misunderstood somewhere, couldn't figure out the following, any helps will be greatly appreciated. The first order correction of the pertubated energy is: \leftψn0\langle H'\rightψn0\rangle Where: ψn0 Is the solution of the unpertubated Hamiltonian. My question is can ψn0 be...

Thank you very much indeed, now I am happy now. Great answer.

thank you very much indeed, and your answer is absolutely fantastic! I am very appreciated it, people like you make the forum a great place!

Dear all: I knew the coherent state is the eigenstate of annihilation operator with a complex eigenvalue, which seriously disturbed me of thinking it. Can anyone give me a simple and understandable picture of what is it, thanks a lot in advance.

hi all, can anyone help me understanding what is the meaning of the mixing state of 2p and 2s? thanks in advance. when an electron in n=2 sate in a hydrogen atom, experience a external em field, then the degenerate states split into 3 classes, which are: 1/sqrt2( 210 + 200 ) with higher...

@DiracRules Thank you for your replay, and it's indeed a great help. Now I am just waiting for more people to come and bring more ideas:) thanks again.

Hi all, I am sure this is a quite simple question but I just can't figure it out, any helps would be greatly appreciated. If a particle stay in a state in a very short time, then by energy time uncertainty relation, it's energy must has a great uncertainty. Also because of energy is propotion...

I have came up some question asking the velocity change of the rocket in its instantaneous rest frame. And I have been taught that in the instantaneous rest frame, v=0, dgamma/dt =0, gamma = 1. if v is always zero, how come to talk about the change in velocity? Thanks in advance

Thanks alxm, great answer, I am now understood. Thank you

Hi all. I am wondering can two photon emerage into one? if think photon in terms of: particle: photon doesn't mind sit in one place with others, once two photons did, what reason they can be separated again? wave: 2 photon with different frequencies are like two waving ropes, put...

Hi,all I found myself so hard to turly understand (spin)angular moment, like spin parallel, triplet state, z component of angular moment etc...always mixed them up and confuse myself. Anyone can help me with understanding these and clarify them would be really helpful. Q1: Sz spin in z...

Hi all. Can anyone tell me why in the equation of the magnetic field due to a nuclear's spin has radius dependence? How come? B=-u0 uI / 2 pi R^3 (sorry about the typing, I don't know how to type a porper equation..) Thanks in advance