Recent content by Gigi

I read that the generator of the O(3) group is the angular momentum L and that the generator of the SU(2) group is spin S. Nevertheless I have some questions. 1. In some books they say that the generator of the SO(3) group is angular momentum L. SO(3) is the group of proper rotations...

No, I am not trying to confuse you at all- there is no point-I think my life is busy enough as it is. I have 20 posts as I only registered 4 days ago! I would also be glad on more comments and discussions...Thus I find your manner impolite. As I said before, a calculation is not an...

It is solved in David Griffiths, Introduction to quantum mechanics. In the case of the time-dependent SE, psi is a function of x and t. Thus you use separation of variables ending with the time independent SE, whose solution is psi(x) as well as a time dependent ordinary differential equation...

Hi! The uncertaintly principle states that we cannot measure precisely the position and the momentum of a particle at the same time. That does not mean that the particle has no precise momentum and position, it just means that we cannot know them. It is like the cat in the box. Is it dead...

Well, I think that these quantum numbers do exist. How? In the sense that they are part of the underlying symmetries of the quantum world. If we talk about the O(3), SU(2) groups, whose generators- that are conserved quantities- are the orbital angular momentum and spin respectively, then the...

Well they are proposing a measurement using experiment-an observation - and you are proposing a theoretical calculation. These are entirely different routes, as in the first case you have a collapse of the wavefunction, in the second you dont. Now in the case they are describing, see what...

Hi:) No, this is not what I meant. Let me put it simply. The uncertainty principle says that you cannot 'measure' the exact momentum and position of a particle at the same time. The idea of measurement implies that there must be an observer that will use some set up to measure. In your...

You will find that most graduate research involves some computational work. I think that you should see it as a positive point, not only in your research, but also from the point of view that computational experience could also land you jobs outside physics if you want to explore more...

Hi...sorry I did not get what you wrote. Is what I said true? Is the SO(3,1) group the Poincare group? Thanks:)

OK, right that is why we need to replace SE. One more point here that I still find unclear. In non-relativistic QM SE is invariant with respect to rotations and translations, if it commutes with the generators of the relevant transformations. The group is SU(2), regarding the rotational...

Well, quantum mechanics is all about measurement and observers. Heisenberg's Uncertainty Principle states that you cannot measure simultaneously the precise position and momentum of a particle. In your case, let's assume that you make a measurement of the position of the photon, thus you...

So far not.

To see whether they would have the same or different gyromagnetic ration, you need to see if they obey the same or different symmetries.

I read in wikipedia the following: 'For example, the Schrödinger equation does not keep its written form under the coordinate transformations of special relativity; thus one might say that the Schrödinger equation is not covariant. By contrast, the Klein-Gordon equation and the Dirac equation...

Well, psi represents the wavefunction of a particle, which as you know has no definite position like classical mechanics. You can imagine that a quantum particle is spread over space, thus the need for a wavefunction to describe it...here it would be good if you studied the free particle and...