Recent content by jujio77

What I am saying is that in one theory gravity can propogate in all the dimensions where as all other particles (us) live on a brane. This is one way to explain why gravity is weaker than the other forces. As to whether you are sold on the idea or not, what's the point?

I don't think the quote is correct. The idea behind that statement is that our visible universe is constrained on a brane, but spacetime itself is higher dimensional. This allows gravity to live on the brane in our visible universe and, also leak into the extra dimensions. It could just be...

It's called the AdS/CFT correspondence. Look it up on Google. There is also a dS/CFT correspondence, but from what I've seen it isn't as popular.

I'll work on that experiment once I finish my perpetual motion machine!

If you are looking for example problems, I would say the best source other than online sources I don't know of would be the Schaums series on Lagrangian Dynamics. They cover many different examples. Of course the best way to learn is to do them yourself! Good luck.

Check any book on quantum field theory. When you calculate the amplitude for each process, whether it be electron electron, or electron positron interaction, you will see which diagrams contribute for each process. Peskin is the common textbook for QFT, so if it isn't an example, it is...

I have a question about the spectrum of particles predicted in string theory. Assuming I have this correct here goes. If I look only at open strings I can predict the particle spectrum and I can get scalars, vectors, spinors, maybe spin 3/2, but no spin 2 particles. We can then look at the...

The math doesn't tell you how the to compactify the spaces though...does it? If so, each space compactify in the same way, yet it seems unlikely? It would be nice if someone found a mechansim which describes compactification process.

I say we go to the course and test it. My guess is there will be no contest, the golf club will make it go much farther.

In the second part, are you asking what would happen if time is reversed? If so, than I say let's also switch left and right. Then we have reversed charge, time, and direction. In this case nothing will change since field theory is CPT invariant. If you want to look at each case...

I may be wrong, but doesn't the weight function have something to do with the coordinate system you are in. If we look at a problem that has spherical symmetry our weight function is W=r^2sin\theta. We know the momentum operator in this case.

If you want the most probably Energy or whatever just think about it this way. The probability density for some operator X, is just psi^* X psi. Find the maximum for this distribution.

It doesn't matter what you are calculating the expectation value of, you should always get the same result in any basis. Your choice of space is just a choice of basis which you integrate out.

2 electrons don't interact in the same way as an electron interacting with a positron. You can see this by looking at the tree diagrams for these interactions.

That is a good question. Let's look at it this way. Assume you did use your value as the wavefunction. Then what would L_z operating on the wavefunction represent. If you choose "A=B=1", your wavefunction is no longer an eigenfunction of L_z, and you have to find a new set of operators...