Recent content by Quantumjump

PhD's in the United Kingdom are definitely open for non-EU students, as proven by the large number of Chinese coming here, however the problem is the funding. Usually, non-EU are funded from their home countries, or through private institutions that promote excellence. In fact, even for EU...

Hi my reply comes a bit late but I wanted to react to the above statement, which, I must say, is absolutely WRONG. Or, should I say, ir RIGHT, if you mean.. the english-speaking world. France has online distance-learning degrees which are not very well known but that completely kills and...

Hi Christine, when you release a ball that is about to fall down, its initial direction will make it to follow a particular spacetime curve (=geodesic) that is different of the one that would correspond to an orbit (which, in fact, is a curve associated to another geodesic). It is wrong to...

not completely right. I know active string theorists in some major universities that never scratch anything related to noncommutative geometry. In fact, noncommutative geometry is in its essence an alternative to string theory. String theorist (well, SOME of them) got interested to NCG because...

look at the attachment, I have added new points and lines to your picture to make the proof clear. We have:x= AB+BC but BC = x' cos (beta) and AB = TM sin beta + Mx' sin beta = (TM+Mx') sin beta = Tx' sin(beta) = z' sin (beta) (because Tx' parallel to z') hence x= x'...

apologies accepted. To be honest, I admit my own post was ambiguous, so no worries about that. :biggrin:

You completely misunderstood my post. Read it again. It's the Poincaré conjecture that has been solved, not the shape of Universe. What Poincaré conjecture allows to deduce is the shape that is associated to every assumed topological structure. This shift the problem to whether a chosen topology...

The issue of what is the shape of the Universe is a consequence of Poincaré's conjecture, and it generalization. This problem has been solved a few years ago by Grigori Perelman.

I'm afraid to say that "direction of the spin" has no real meaning either. Remember that spin considered as an "intrinsic angular momentum" is only an analogy. That analogy works okay with spin zero particles, but crashes down with spin 1/2 particles. The fact that individual photon have spin 1...

I think you are referrring to a particular case of a general result called Poincaré Lemma, which states under which condition a function called "potential" can exist, in a wide range of situations. It is indeed an extremely powerful result.

Eh? Changing the spin of a photon? I have the feeling to have missed something here: photon's spin is fixed to ONE by quantum field theory, when performing the second quantization of the electromagnetic field, so how damn can you change the spin of a photon? :bugeye: Is there any reliable...

I would recommend two books: Lie Algebra in Particle Physics, from Howard Georgi Quantum Mechanics- Symmetries, from Walter Greiner. These two books complement each other in the sense that Georgi spans a wide range of techniques, but is not always rigorous and mainly focuses on calculational...

I would suggest Serge Lang's Undergraduate Analysis. To be honest, i didn't study it, but I studied his Linear Algebra and his Undegraduate Algebra, and I found them to be extremely useful and throughly well explained (being understood that "well explained" doesn't necessarily mean "easy")

Playing chess just to play chess of having fun, is great, but I think that trying to be good at chess specifically in order to get more mathematical maturity is a waste of time. To get mathematical maturity, read (and study) Euclid: even if it only deals with (not so) elementary geometry, you...

As far as I know, engineering mathematics requires a good training in exercise solving, rather than being able to produce proofs. It is mainly a question of calculational training, and you can reach a relatively good level if you take the time to do as many exercises as you can, starting from...