Recent content by npnacho

first of all, thanks for answering. I think I'm having a notation problem... I'll try to explain it: the fact that for any index \mu you have n^{ 2 } - 1 real numbers A_{ \mu }^{ a } ( x ) is always true. it doesn't depend on which representation you decide to use, am I right? so the fact...

yes, but that's in the fundamental representation. in the adjoint representation the dimension of the generators is equal to the number of them, for example in SU(2) you define the adjoint representation as: then, for SU(2), in the adjoint representation you have three 3x3 matrices, for...

hi! in the first page of the attached pdf, after the title " 't hooft double line notation", he says that we have to consider the gluon as NxN traceless hermitian matrices to convince ourselves about the double line notation. there is my question: if you want the indices a,b to run from 1 to...

thanks! i'll take a look.

ohh, man. that's really good. so that's why we have to resign to the idea of assigning physical meaning to the coordinate time and treat it like a global parameter only, right? (except in extreme cases like this one when we know that it coincides with the propper time of a particular observer...

i've never heard "distant time" or "local time" (maybe i know what it is but not in english, i don't know...) what do you mean with that?

of course, one way to do that (calculate the elapsed in the observer's clock between two events A and B) is to compute the geodesics of two light rays which come out from A and B and find the times they reach the observer (this is what wannabeNewton tried to say me before, i think) but i was...

i wasn't referring to the sign, i hope i made my question clear in my previous post, but what i say is that to get ##t_2-t_1## as ##r\rightarrow \infty##, you are measuring the time of events in infinity, that's way the propper time of the observer at infinity matches the coordinate time in...

first of all, I'm sorry if I'm being repetitive, i know you've answered my question already, the thing is i don't understand that, i''l try to explain my problem with another example: that was exactly my initial question, i.e: the coordinate time (on my own reference system) has something...

i don't understand what coordinate time is... so I'm hardly confusing it with propper time i'm still having the same question: in the SR case I've mentioned above, the time elapsed isn't propper time, because we are talking about the trip of a spaceship which is not at rest in our...

oh, thanks for the differentials, i just forgot. now I've corrected that. anyway, I'm not sure if my question was totally clear... in the scharzschild case, the coordinate time matches the propper time measured by an observer at spatial infinity because ##\sqrt{1 - 2M / r}## → 1... but what i...

well, i have been reading hartle's book and it's clarified many of my doubts... but i still got one: suppose someone gave us some metric, a diagonal one to simplify, say: dS^2=g_{00}(cdx^0)^2-g_{11}(dx^1)^2-g_{22}(dx^2)^2-g_{33}(dx^3)^2 where the components of the metric tensor, g...

ah! and for the GR part i think I'm going to use "gravity" by james hartle... but another recommendations will be welcome.

the class was a couple of years ago, now I'm starting to study for the final exam... but between the strange education system we have here in argentina and my little memory... it's like i wasn't studied GR in my entire life... this couple of things were part of the first classes (the subject...

what i mean is that, in virtue of the equivalence principle, an accelerated frame in vacuum must have a non flat metric, so i suppose that the metric "observed" by a particle at rest in front of the sun it's not the same that the metric observed by another particle that is accelerated with...