Nicholas Kang Posted June 11, 2014 Share Posted June 11, 2014 Is it possible to have a third charge apart from the ordinary positive and negative? Maybe the third charge would be a charge that can alter or shift its charge from positive and negative at a specific interval or simultaneously? Link to comment Share on other sites More sharing options...
ajb Posted June 11, 2014 Share Posted June 11, 2014 Yes, and we have such things, but they are not the charges associated with electromagnetic theory. For example we have colour charge in quantum chromodynamics and technically they are to do with the representations of the Lie group SU(3), which is the gauge group of QCD. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 11, 2014 Author Share Posted June 11, 2014 How many charges are there in quantum chromodynamics? Link to comment Share on other sites More sharing options...
ajb Posted June 11, 2014 Share Posted June 11, 2014 Just thinking about quarks we have red, green, and blue, and then antired, antigreen and antiblue for the antiquarks. Gluons take a mixture of two colour charges. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 11, 2014 Author Share Posted June 11, 2014 May I ask you one question? How to draw Feynman Diagram? How is it related to the Perturbation Theory? Link to comment Share on other sites More sharing options...
ajb Posted June 11, 2014 Share Posted June 11, 2014 May I ask you one question? How to draw Feynman Diagram? How is it related to the Perturbation Theory? This is getting technical... You have to separate the action into a free piece and an interacting piece, do a little tick and then realise you can expand your action as a formal power series a bit like the Taylor expansion of exp. This is the basis of perturbation theory. You can then look at each term in your expansion and associate with it a Feynman diagram. Interestingly, once you know the basic building blocks of the diagrams you can write your expansion in terms of diagrams only, but you should remember they correspond to terms in a formal series. It has been a while since I actually did this for QED, but it was not too hard. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 11, 2014 Author Share Posted June 11, 2014 But it is too hard for me. Yet, I find this topic fun. Scientist at the LHC keep on discovering new particles or more precisely elementary particles. Isn`t it sound crazy to continuously just stay at the ATLAS, CMS etc. just to play and run the particles to just collide and no more than that? I have no idea of what this means: You have to separate the action into a free piece and an interacting piece, do a little tick and then realise you can expand your action as a formal power series a bit like the Taylor expansion of exp. This is the basis of perturbation theory. You can then look at each term in your expansion and associate with it a Feynman diagram. I am stupid. Can you please tell me more formally or somehow more clearly. Your analogy is confusing me. Sorry to say that. Link to comment Share on other sites More sharing options...
ajb Posted June 12, 2014 Share Posted June 12, 2014 Can you please tell me more formally or somehow more clearly. Your analogy is confusing me. Sorry to say that. The best thing to do is pick up a book. I don't have the will or time to brush up on all the details and teach you. I am happy to direct you though. Start with the Feynman rules for phi^4 theory and from there look at QED. You could try Ryder's book. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 12, 2014 Author Share Posted June 12, 2014 Ryders`s Book? I will find it anyway. Thanks. Link to comment Share on other sites More sharing options...
Strange Posted June 13, 2014 Share Posted June 13, 2014 I am stupid. I don't think you are stupid. But you are young and there is a lot to learn. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 13, 2014 Author Share Posted June 13, 2014 (edited) I am young and there is a lot of thing to learn. I agree with this fact. Edited June 13, 2014 by Nicholas Kang Link to comment Share on other sites More sharing options...
pwagen Posted June 13, 2014 Share Posted June 13, 2014 He didn't say he knows you're not stupid. He said think. Stop being so defensive, it's contraproductive. Link to comment Share on other sites More sharing options...
Nicholas Kang Posted June 13, 2014 Author Share Posted June 13, 2014 (edited) I have to violate Mr.Ophiolite`s rule. Sorry. It is my fault. Actually, I didn`t look throughout his statement carefully. I had edited my post. Edited June 13, 2014 by Nicholas Kang 1 Link to comment Share on other sites More sharing options...
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