Recent content by llorgos

I guess there are not too many of us being famous enough ;)

This is a very interesting question. I am a having a similar doubt. I guess it depends on what you want to do. If you want to stay in academia, I think, what is important is the department coz if you have a prestigious department it means you a) collaborate with top researchers, b) you get to...

Hello, I am facing a difficult dilemma. I am between taking the GRE exams and go study in USA and at the same time I am holding an offer in studying in Europe at a relatively new university but with two very famous and kind professors. On one hand, holding a master in theoretical physics, and...

Thanks for your help. I cannot consider the US since I have no time to take the GRE's currently. Also, it is very expensive to apply to those universities. That is why I am asking for Europe. Of course I know the groups I want to work with, and the univerisities, I just want to see what other...

But 't Hooft is not working in strings.. I am not sure why you say that he does. In Utrecht for example there is de Wit who is an actual string theorist but 't Hooft certainly is not (I think he currently works on some strange reformulation of QM). Also, as I pointed out, I am interested in...

Hi all! I am ready for applying for my PhD which I want to be on String Theory and in Europe. I am finishing my master's degree in Theoretical Physics and currently I am researching Holographic Renormalization for asymptotically non-AdS space-times. I am interested in all aspects of String...

Hi! I keep hearing that in the large N limit (so I am talking in specific AdS/CFT but more general too I guess) U(N) and SU(N) are isomorphic. So if I construct, say, the ## \mathcal{N}=1 ## SYM Lagrangian in the large N limit, I can take as gauge group both of the ones mentioned above...

Hello! Can someone explain to me, as clearly as possible, how one can find irreducible representations of Lie groups (and especially in the context of finding the spectrum of e.g. the bosonic string theory)? I am following BB&S and Polchinski but I cannot really understand how they...

would it be possible to talk a bit more about the second part, the compactness or non-compactness of a Lie group? In any case thank you very much.

I read that in string theory the Virasoro algebra contains an ##SL(2,R)## subalgebra that is generated by ##L_{-1}, L_{0}, L_{1}##. I read that this is the non-compact form of the ##SU(2)## algebra. Also, that as ##SU(2)## and ##SO(3)## have the same Lie algebra, so do ##SL(2,R)## and...

It is a goldstone boson coming around in the R_{\xi} gauge. Actually it is the charged one.

Hi! I have to prove that the amplitude of the process \gamma \gamma \to W^+ W^- does not depend on the gauge we will choose, R_{\xi}. So I use the most general expressions for the propagators and vertices. I find 5 diagrams. One that involves only the 4 fields and a vertex, 1 t and...

Hi. If you want I can write it as \frac{\partial X}{\partial t} = -\frac{\partial T}{\partial x} where T = T(x,t) and X = X(x,t) in general. I know they must be equal to a constant. Please correct me if I am wrong. Thank you.

Hi! I would like to ask what is the general solution of the following differential equation \frac{\partial X_x}{\partial t} = - \frac{\partial X_t}{\partial x} Thank you very much. P.S. If you have some good resiource about this tyoe of equation to recommend please do so.

Ok. Thank you very much. Let's see if I can make any progress.