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chicchorea
(Member Profile)
Thanks!
HAPPY BIRTHDAY ! ! ! ! ! ! !
...AND MANY MORE ! ! ! ! ! ! !
ENJOY ! ! ! ! ! ! !
Deano
(Member Profile)
Thanks!
In reply to this comment by Deano:
*promote
oritteropo
(Member Profile)
Thank you, kindred spirit!
In reply to this comment by oritteropo:
*quality *doublepromote
oritteropo
(Member Profile)
Thanks!
In reply to this comment by oritteropo:
*quality
Quantum Field Theory Made Easy! - Feynman Diagrams
@offsetSammy (I'm a physicist.):
Basically what @GlasWolf said. There are in principle an infinite number of things that can happen between the input and the output (you may for instance always add an extra self-energy term as shown in the video at 5:30 onwards), but usually only a few of all these infinite possible processes make up most of the total process.
To understand what I mean by that, it's important to remember that we are talking about quantum physics here. When we say that the different subprocesses have different probabilities, we don't mean that the particles choose (with a certain probaility) one of the possible Feynman diagrams to follow. No, in fact all the possible diagrams are followed at the same time. But the fact that some of the diagrams are more likely than others means that they are weigthed more heavily in the calculations. All the diagrams that contribute a tiny part to the total process can therefore be ignored, making the calculation much easier. And if your calculations turn out incorrect, you can simply add a few extra diagrams and try again.
This is also related to why the Feynman diagrams at first were met with scepticism by the physics community. Particles behave according to quantum mechanics, and don't go along straight lines as in the diagrams. But it turns out that they are very useful for translating the inherently counter-intuitive quantum physics into a language that is easier for the human brain to understand. They were therefore accepted as a very valuable tool, even though they are technically unphysical.
oritteropo
(Member Profile)
Thanks, dear!
In reply to this comment by oritteropo:
*quality
oritteropo
(Member Profile)
Thanks a lot for the promote and quality!
In reply to this comment by oritteropo:
*quality
GeeSussFreeK
(Member Profile)
Here's a book I think you will like
http://www.amazon.com/Eternity-Here-Quest-Ultimate-Theory/dp/B004Q7E0MM/ref=sr_1_1?ie=UTF8&qid=1319719988&sr=8-1
In reply to this comment by GeeSussFreeK:
</rant of one of my favorite subjects!>
Lawdeedaw
(Member Profile)
Fixed!
In reply to this comment by Lawdeedaw:
*dead
Sixty Symbols - Neutrinos Faster Than Light
Time travel might still be out of the question though, even with faster than light neutrinos:
http://blogs.discovermagazine.com/cosmicvariance/2011/09/24/can-neutrinos-kill-their-own-grandfathers/
schmawy
(Member Profile)
Thanks, magnificent you!
In reply to this comment by schmawy:
*doublepromote
Vi Hart and sillybands
snakesnakesnakesnakesnakesnakesnakesnakesnakesnakesnakesnakesnakesnakesnake
Fusionaut
(Member Profile)
Yay! Sifted thanks to you!
In reply to this comment by Fusionaut:
*promote
chicchorea
(Member Profile)
Thanks a lot! And happy Easter to you too; may fourscore chocolate bunnies hop your way.
In reply to this comment by chicchorea:
And how excellent...
Congratulations on the Diamond. Well deserved.
Fusionaut
(Member Profile)
Thanks! With all this snooking around in my PQ, I'll have a diamond myself soon!
In reply to this comment by Fusionaut:
*promote