Feynman Definition and 649 Threads

Homework Statement In an ABC toy theory, the only allowed vertex is one that couples A, B and C. Thus there are no AAA, ABB, ACC...ect vertices allowed. My question is suppose a diagram has na external A lines, nb external B lines, and nc external C lines. Develop a simple criterion for...

The Perimeter Institute has a talk on the Feynman chessboard / checkerboard model scheduled for a few days from now. This will be recorded and you can play it back, sometime after November 18th. Links: Speaker(s): Garnet Ord - Ryerson University Ord's website...

Hello I have to calculate symmetry factors for the following feynman diagrams for my qft class, and would be hugely grateful if anyone could point out any mistakes (I'm sure there are lots!) that I've made. http://picasaweb.google.com/jessicagreerstanley/Physics#5259179071440262450"...

Hello nerds. I was discussing Richard Feymnan the other day and his generally low opinion of psychologists (not unreasonable, at least when he was around). However I remembered a story of his about how he thought that in cowboy movies the guy who draws his weapon first (usually the bad...

I just got a copy of Feynman's lectures on Physics the other week. They are very interesting. Near the end of the 4th chapter, he begins discussing conservation laws. One of the laws he gives is the conservation of baryons. I noticed early in the first volume, the lectures were published in...

what does Feynman's diagram prove? i know it deals with something "going back in time"

Well, I have got hold of Feynman's Lectures Volume 1,2,3... I am trying to understand UnderGrad physics through self-study at home... Are those 3 books enough to understand (at least conceptually) UnderGrad level physics?

I need to insert the slash notation, A\!\!\!/ , into a Mathematica document. I have searched high and low, but find nothing on this.

Hi! I wonder if the Feynman rules in momentum space can also be applied to disconnected diagrams. So aussume I have a disconnected Feynman diagram 1 , i.e. the product of two connected Feynman diagrams 2 and 3. I can translate my diagrams with the position space Feynman rules to explicit...

Can anybody help me by explaining how to write down the Feynman rule corresponding to a term like ieA^{\mu}\phi^{\ast}\partial_{\mu}\phi I am confused about the presence of the derivative term. Terms have usual meaning.

"You know, the most amazing thing happened to me tonight. I was coming here, on the way to the lecture, and I came in through the parking lot. And you won't believe what happened. I saw a car with the license plate ARW 357. Can you imagine? Of all the millions of license plates in the state...

I intend to refresh my knowledge in physics, and exercise a great deal of math. I will do some heavy calculus, dif, linear algebra work with some quantum mechanics added onto it. The thing is I also want to read the feynman lectures I bought long ago. Do you think that it is reasonable to...

Okay I've just paid £50 for the feynman lectures on ebay, waiting for it in the post. Anyone here have it and can tell me whether I've wasted my money (i'm 17 and havn't even started learning particle physics yet, I've just finished AS levels). Am I going to understand it or not? Also is...

I would like to clearify the connection between n-point functions, Feynman diagrams and S-matrix. I do not want ( yet) to understand the detailed derivation of the LSZ reduction formula, just the rough connection between the n-point function on the one side and the S- matrix on the other...

Just out of curiosity, how hard is Fitzpatrick's online Graduate version of quantum mechanics compared to the Feynman lectures and Sakurai's book?

Hi, I was just reading feynman's nobel lecture the other day ("The Development of the Space-time view of qed") where he discusses the problems associated with his initial view that an electron does not act on itself but merely acts on other electrons. He talks about the "force of radiation...

in peskin-schroeder and http://www.hep.phy.cam.ac.uk/batley/particles/handout_04.pdf" the amplitude for e^-e^+\rightarrow \mu^- \mu^+ is written using feynman rules as follows -iM=[\bar{v}(p_2)(-ie\gamma^\mu )u(p_1)] \frac{-ig_{\mu\nu}}{q^2}[\bar{u}(k_1)(-ie\gamma^\nu )v(k_2)] but what...

Homework Statement I’m trying to learn Feynman diagrams from Peskin and Schroeder. I’m stuck right now on page 91-93, especially about constant factors and symmetry factors. Equation 4.44 and the two constants 3 and 12 in it make perfect sense to me. The trouble starts with 4.45. I understand...

Feynman refers to "renormalization" as a dippy process on p.128 of his book "QED - The Strange Theory of Light and Matter". His words are: "The shell game that we play to find n and j is technically called renormalization. But no matter how clever the word, it is what I would call a dippy...

"...the observed masses of the particles.." R. Feynman Feynman wrote: "Throughout this entire story there remains one especially unsatisfactory features: the observed masses of the particles, m. There is no theory that adequately explains these numbers. We use these numbers in all our...

In reading Feynman's "Lectures on Physics", volume 2 I have a question and have included a scan of a small section from the book. Feynman was a big fan of using the Principle of Virtual Work, but his explanation, as least insofar as how he used it is wanting, at least for me. The attached...

1. Feynman says all of electromagnetism follows from Maxwell equations. 2. Somebody (Pointing to a Feynman diagram of a photon/electron reaction) said all of electromagnetism is in that one diagram. So, can anyone help me with these two questions: how does point 1 come from point 2. And, how...

Hi, This question is quite relevant to some other posts at the end of the very long "very simple QFT questions" thread, but I've decided to start a new thread with a heading which is more indicative of what I wish to ask the group. As a question, it's a fairly concise, but the analysis is...

"Feynman integration trick" - textbooks? I was quite impressed by the use of the parametric differentiation e.g. in integrating sin(x)/x in https://www.physicsforums.com/showthread.php?t=80735. Can anyone recommend textbooks that cover this use as a strategy in evaluating integrals? Ideally...

What distinguishes Fermions form Bosons in Feynman diagrams?

[SOLVED] feynman rules Hi , It is a simple question from the book of david j .griffiths :"introduction to elementary particles" (6.11) Homework Statement (a) Is A--->B+B a possible process in the ABC theory (feynman rules for a toy theory) (b)Suppose a diagram has nA external A lines , nB...

is there any program that can generate the feynman diagram for a specific perturbation of n-order contributions to Green function?

I'll be studying electromagnetism next sem (January) and I thought reading Feynman before the proper start of course will be useful, but Feynman himself said( in the preface) that he did not do much creation in vol II. So, is there any other Feynman sort of book on electromagnetism or I should...

Hi, I've got a Masters in Physics, but always feel that I'm missing out slightly by not knowing and appreciating the beauty that there is in all the maths I never had cause to study in my physics degree. Is there a book (or set of books) that does for maths what the Feynman Lectures do for...

Hello all. Firstly, know that I need a little handholding. We are told that in the detail, the actual behavior of matter is better modeled with quantum theory concepts, apparently to a impressively proven accuracy, even if the mathematical aids involve counterintuitive, though useful, notions...

I read from 'strange theory of light and matter' by feynman that light also travels faster and slower than C but on an average it travels at C..can anyone explain the reason behind or give me some links..

Hi everybody, I am a MAC OS X user, and I have a trouble with feynmf package in latex. I have downloaded the package from CTAN website and followed the instructions for installation. Then in my latex file I coded a generic 2-body scattering process labeled as "generic", after typesetting...

Hi! I need some help with latex. I need to draw Feynman diagrams and it seems that the package feynmfm relies on Metafont, which I really don't even have the slightest idea as how to use it. Anyway, I tried to find a good tutorial on the subject (metafont) but it looks like i will need some...

Has anyone read the Feynman Lectues? Is it worth getting if you are looking to further establish a good grasp of the fundamentals?

I have posted a question on the Tutorial subforum because there was already a thread on that subject but I figured that people here may be more likely to be able to help me out https://www.physicsforums.com/showthread.php?p=1313121#post1313121 Thanks! Patrick

I was just reading the Feynman Lectures on Physics when Feynman discussed virtual work. Unfortunately, I found his explanation somewhat confusing. The following are the three examples Feynman uses in order to illustrate the principle of virtual work. 1. 2. 3. I'm trying to...

Does anyone know where to download the Feynman lectures at? Thanks

Have anyone read "Surely You're Joking Mr. Feynman"?? Have anyone read "Surely You're Joking Mr. Feynman"?? What did you think of it? I only read about half and the the library wanted it back.. But I thought the first half was good, and a little bit funny too..

Homework Statement I am pretty sure it's been done many times before, but I can't seem to figure it out: Consider the collision 1 + 2 -> 3 + 4 in the lab frame (2 at rest), with particles 3 and 4 massless. Derive the forumla for the differential cross section Homework Equations We have...

Greetings all, If you are like me you have a profound respect and admiration for Richard Feynman, the father of QED. Rarely does humanity produce such a brilliant mind and with such an affable personality to boot. Below is a link where you will find several Caltech lectures, eBooks and...

I have some quotes from various books I have read recently, that I would love to hear your thoughts on: Richard Feynman: "All these [chemical] rules were ultimately explained in principle by quantum mechanics, so that theoretical chemistry is in fact physics. On the other hand, it must be...

I have always seen these books in the stores, and such, and they're 100 on amazon (which is a heck of a lot better than B&N) and i want them, but then again they'll probably shoot right over my head. I'm working through my first year of high-school physics. I have read quite a few books on...

Dear PF, I would like to thank you for existence of Physics forums since it appears very helpful. Dear PF, I was reading one paper and trying to derive Feynman rules for some vertices, but I could not get the same result as given in paper, as a guideline I use ‘t Hooft’s diagrammar and the...

Amazon has a list of 100 bestseller books in physics category. this includes popularizations, biographies, textbooks, Carl Sagan, Brian Greene, intelligent design, iffy-physics-of-the-supernatural, physics cartoons and comedy, ANYTHING if it has a connection with physics*. So the competition is...

OK. I've googled for about an hour yesterday and couldn't find where to get "Think different " poster feat. Feynman. :frown: there are two actually, the one where Feynman is in his sixties is really hard to find. :mad: any ideas on where I can buy it?

I swear this book does not actually exist. Well, unless I'm willing to spend between $300 and $1200 (no, that's not a typo). Am I correct in my suspicion that there was only a single printing of the text back in '65? Does anyone actually have a copy?

On page 92 (Figure 58) Feynman states: "The amplitude for a coupling is a number that I will call j; it is about negative .1 for the electron (this number is sometimes called the "charge"). Charge?? I don't get it. Would appreciate an explanation?

http://arxiv.org/abs/hep-th/0611042 Hidden Quantum Gravity in 4d Feynman diagrams: Emergence of spin foams Aristide Baratin, Laurent Freidel 28 pages, 7 figures "We show how Feynman amplitudes of standard QFT on flat and homogeneous space can naturally be recast as the evaluation of...

I've been given a small project to ease me into life as a PhD student and part of it involves working out Feynman rules for scalar bosons coupling to gauge bosons. I've been reading through Peskin and Schroder Chapter 9 and want to clarify if I've got my understanding right of how to do it...

I'm far from well versed in physics, but I'm trying to understand something about a Feynman diagram I saw. The diagram shows an electron and positron annihilating, and producing a quark/anti-quark pair and a gluon. I recently saw a special on the discovery channel that said matter/anti-matter...