Recent content by liorde

I excluded time because I used a 2D space analogy, which was easy to illustrate in a figure. I'm interested in the idea, so it doesn't matter if I use time or not.

Hi, I'm confused about the exact interpretation of Noether's theorem for fields. I find that the statement of the theorem and its proof are not presented in a precise manner in books. My main question is: what is the precise heuristic argument that leads to Noether's theorem? The question...

So what is the formulation? Or where can I find it? When I tried to write down the Poisson bracket formulation myself, I ran into problems. Here is my attempt: The coordinates are {A^\mu }({\bf{x}}) where \mu runs over the space-time indices and {\bf{x}} runs over all space points. The...

I am a physics student, doing my graduate degree. I am wondering if anyone else feels like me concerning the following topic: Physics is usually presented in a very imprecise way, and it would be much easier to understand if it would be presented more precisely. I felt this way towards all...

Since I couldn't find any reference on the subject of Poisson bracket formalism of classical field theory, I'm posting a few question here: A) What are the Poisson brackets of the source-less EM field? B) Does the law that the Poisson brackets between a dynamical variable and its conjugate...

Hi, Question about nuclear weapons: Often you hear about a missile that is capable of carrying a nuclear warhead. But actually, why can't any missile be capable of this? Just take your favorite missile, build for it a nuclear warhead which is the same shape and size as the missile's...

I'm sorry, but at the time (and for a long while) I didn't have any means of connecting to the internet, for technical reasons... And now I wanted to ask some more questions about this subject, but to approach it from a different angle, and that is why I opened a new thread (I also posted it in...

Maybe the word "internal" should have been used... I'm not sure what I mean, but I hear people referring to spin as generating an "internal" transformation. In non relativistic quantum mechanics (of particles), when we want to discuss spin we add to the wave function a parameter s, which...

(if I am not even wrong, please let me know :smile:) The generators of the (proper-orthochronous) Lorentz transformations are usually denoted by {J_{\mu \nu }} or by {M_{\mu \nu }}. They consist of angular momentum generators and boost generators. When discussing spinors, the notation changes...

Hi, Thanks again for the answers! Your last paragraph raises some of my original questions again: Thanks

Thanks for your help! I'm still a little bit confused... So you're saying that the commutation relations of the algebra (= the structure constants) do not include all the information about the group? Two algebras (e.g L and L+S) can have the exact same commutation relations but correspond to...

You say that But \left\{ {{L_{\mu \nu }}} \right\}, defined in (1.2.24), is an "arbitrary" set of operators that satisfy the commutation relations, so it by itself should give rise to all the different representations (corresponding to the different eigenvalues of {J^2}) with no need to add...

Ramond, Field Theory: A Modern Primer, Second Edition, Chapter 1, page 7. Here is the link: http://books.google.co.il/books?id=Ctr9K61fY4kC&lpg=PP1&pg=PA7#v=onepage&q&f=false Look at the last paragraph. I've seen at least two more references using this method (although I might have exaggerated...

When constructing the Lie algebra of the Lorentz Transformation, the references usually start with an infinitesimal proper-orthochronous transformation, and then find the infinitesimal generators. Let's call the set of these generators L. after finding L, the references usually compute the...