Recent content by Los Bobos

Hi Chris, this was related to the difference between the invariant mass and the Newtonian momentum. Equivalent effects do not mean equivalent physics in every case. And again let's use only invariant mass. And 4-momentum :).

I don't want to be annoying, but there is a reason why energy-momentum tensor is called energy-momentum tensor and not mass scalar.

In the books which I have used your exercise is the definition of the Lie group :smile: ?.

lalbatros, as I pointed out earlier, Rindler horizons are observer dependent and thus unphysical. I am kind of losing your point here...

Simple answer: Classically we cannot explain the threshold frequency. Also in classical case the energy of the emitted electrons would depend on the intensity of light, which is not the case in experiments.

notknowing and Lelan Thara, if read the faqs I think you noticed the main point that relativistic mass is used when trying to find correspondences with Newtonian mechanics. When we are using special relativity we can only use invariant mass, as it is the mass of the particle. For example in QED...

No. In interactions we only have the invariant mass. You have to think about the meaning of the momentum 4-vector in relativity. Naturally, if one wishes it is possible in some cases to try explaining some things (illogically) with the relativistic mass. Yes it is. You could also look at...

Yes, but for me there is no logic in calling the temporal part of the 4-momentum "mass" as it is not mass which is the norm of this 4-vector :). I would like to see for example the lagrangian of QED written with this weird mass. "The road to emitter theory is paved with relativistic masses" ;).

jtbell, you are completely right in the statistical sense :smile: , but for me there is only one mass. Relativistic mass causes some logical inconsistensies rising from incorrect use of simultaneity (at least it seems so to me). Relativity is not classical and therefore it makes no sense to me...

Mass is the norm of the momentum 4-vector. It is the same and the one and the only everywhere. Your second question I don't understand.

Regarding the "tipping of lightcones" can someone point a coordinate system for Schwarzschild black hole, where this does not happen? At least with the usual suspects this seems to happen ("the nature of dx -> dt" in the usual way or the relationship of the light cones and the tangent of...

The only physical mass is the invariant mass, the other one is just a teaching tool.

The increase of mass with velocity is just an evil pedagogical plan and a historical misunderstanding (this was included in the Lorentz-Fitzgerald theory (if I remember correclty, transverse masses and so on)). This was a good text about the subject...

It is actually more consistent to say, that from SR we know that mass does not increase with velocity. Here you would have to think what is momentum in SR. And of course the biggest problem of elementary QM, the difference in the handling of spatial and temporal coordinates.

I will try to explain this a bit better (it's a while time since I've worked with gr). The Rindler and Schwarzschild horizons are very similar and actually for both of them the singularity at the horizon is just a pseudosingularity - for Rindler, as said before, it can be only seen by observers...