Recent content by gremezd

Yes, I have read wikepedia both on a branch point and complex logarithm. But how do we interpret singulartities: do they constitute the essence of physical quantities or, as you say, they make these physical quantities ill-defined? and have to be got ridden of? I found it interesting that...

I have been reading Chapter 7 of Peskin & Schroeder about full propagator, the Kallen Lehman spectral representation, and got stuck at the branch cut singularities and at the complex logarithm of negative numbers. I have posted in the Analysis forum (but have not received any answer) the...

Hi! Does anyone know what a branch-cut singularity is? I have been trying to understand its importance in physics, but I got lost. I would guess that a singularity in physical context should mean that the value of a function should become very big near that singularity. But if we take complex...

I'm planning to apply for a MSc studies in Theoretical Physics. I found that LMU and Utrecht offer 2-year, and not 1-year, programs, which I like. What would you choose for a broader education in this area?

It would be nice if someone commented a couple of propositions by Peskin and Schroeder in their QFT book in p.166. There they say that when the helicity is conserved in the high energy Compton scattering, one unit of spin angular momentum is converted to one unit of orbital angular momentum...

So, summing up all the replies it seems, that Florida would be an average choise in the USA. However, I live in a small European country and now I am in the fourth year of my undergraduate studies. I would say that I feel passion for physics and would like to obtain a deep and broad...

So, from the ratings Hippo posted it seems that if one wants to quietly study at the UF, he should not expect do this at his room?

Vanadium, I agree, that the point is to learn as much as you can. And you can pursue this at any university. However, I believe, that if you enter a better university and get funding, you can concenrate on physics with a great help of very good professors and that way to save your time compared...

I consider entering the University of Florida for graduate physics studies. Do you know what the ranking of the University is? Is it worth going there? Some good or bad experiences from this institution? Could maybe anyone compare studies at Florida and at the best institutions, such as MIT...

Clem, do you mean that the value of chirality (left-handed or right-handed) is "god given" to a particular electron and cannot change in its lifetime? Or, as you say, depending on interaction, all electrons are left-handed or all right-handed? (I just try to create some image of what chirality...

Thank you, nrqed, for pointing out my mistake. I appreciate it :)

Does anyone know how to differentiate an exponential, which has an operator in its power? I found it quite a trouble in Peskin's QFT (page 84, formulas (4.17), (4.18)). Here we have these two formulas of Peskin: U\left( t,t_{0}\right)=e^{iH_{0}\left( t-t_{0}\right) }e^{-iH\left(...

OK. Let's think of a massive electron. As long as it cannot propagate with the speed of light, it cannot have definite helicity, as we can boost to the other frame, where our electron's helicity would change. But again, as long as our electron is massive, it will have both parts, the left-handed...

What is the difference between chirality and helicity? I know, that helicity shows the handedness of the particle. For example, we have a right-handed electron if its spin is aligned in the direction of its propagation. The concept of chirality is a bit similar to that of helicity, but something...

Ok. I guess, I found the answer myself. Everything is well, when we account for the phase change by pi after reflection from optically densier medium :)