Feynman Definition and 649 Threads

Richard Phillips Feynman (; May 11, 1918 – February 15, 1988) was an American theoretical physicist, known for his work in the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, as well as his work in particle physics for which he proposed the parton model. For contributions to the development of quantum electrodynamics, Feynman received the Nobel Prize in Physics in 1965 jointly with Julian Schwinger and Shin'ichirō Tomonaga.
Feynman developed a widely used pictorial representation scheme for the mathematical expressions describing the behavior of subatomic particles, which later became known as Feynman diagrams. During his lifetime, Feynman became one of the best-known scientists in the world. In a 1999 poll of 130 leading physicists worldwide by the British journal Physics World, he was ranked the seventh greatest physicist of all time.He assisted in the development of the atomic bomb during World War II and became known to a wide public in the 1980s as a member of the Rogers Commission, the panel that investigated the Space Shuttle Challenger disaster. Along with his work in theoretical physics, Feynman has been credited with pioneering the field of quantum computing and introducing the concept of nanotechnology. He held the Richard C. Tolman professorship in theoretical physics at the California Institute of Technology.
Feynman was a keen popularizer of physics through both books and lectures, including a 1959 talk on top-down nanotechnology called There's Plenty of Room at the Bottom and the three-volume publication of his undergraduate lectures, The Feynman Lectures on Physics. Feynman also became known through his semi-autobiographical books Surely You're Joking, Mr. Feynman! and What Do You Care What Other People Think?, and books written about him such as Tuva or Bust! by Ralph Leighton and the biography Genius: The Life and Science of Richard Feynman by James Gleick.

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  1. J

    Why Are the Feynman Lectures on Physics So Revered?

    What is it about the Feynman lectures on physics? Everywhere I hear about them they're refer to as great, awesome for science and what have you. But what makes them so revered? What sets them apart from say the Suskind Lectures or MIT OCW? Perhaps I am to young in my career to have learned...
  2. N

    Richard Feynman's Original Work: Discover & Explore Now!

    There is a lot books written by Richard P Feynman. but Which one deals with his original work. I want to read that.If you have already read that then give some description also. Recently I read Maxwell Treatise on E&M. Book is Great but not readable for me.
  3. S

    Photon-Massive Vector Boson Vertex Feynman Rule

    1. The Problem I am trying to find the feynman rule which corresponds to the addition of an interaction term to the QED lagrangian which couples the electromagnetic field to a neutral massive vector boson field. In this problem, $$k^\mu$$ corresponds to the photon 4-momentum and $$q^\mu$$...
  4. E

    Vertex Feynman Rule Derivations

    Alright, this is a pretty low level / silly question but I am having some issues. I would like to get the vertex rule for an interaction that has a field tensor involved like this... \partial_\mu Z_\nu -\partial_\nu Z_\mu do I treat the two Z's as separate fields? For a generic field...
  5. V

    Rules to compute Feynman Diagram with the Feynman rules

    Hello, I am trying to compute feynman diagrams with the feynman rules but I encounter some difficulties... Since the gamma matrices, spinnors, etc do not comute, the ordering of the different factor from feynman diagram has an importance. Is there some rules that say where to begin and in...
  6. Z

    Can Kaon Decay Violate Lepton Number Conservation?

    Homework Statement I am asked to draw a feynman diagram of K^- \rightarrow \mu \nu Homework Equations K^- consist of s\bar{u} The Attempt at a Solution I wonder what the direcion of the arrows should be, my guess is something like the attached image. edit: Ah, where the left u shoudl be an...
  7. G

    Changing the sign of 4-momenta in Feynman diagrams

    If a Feynman diagram only involves bosons, then can you multiply all external 4-momenta by negative one, and still get the same amplitude? Looking at the Feynman rules this seems true. If the diagram has a fermion (as real or virtual particle), then it seems this is no longer true. I just...
  8. M

    Create Feynman Diagrams online

    I need to put some Feynman Diagrams in a paper that I'm writing on my Mac (Lion) with Texpad, but I don't know how to create them in Latex (I tried it with some things I found on google [feynmf], but it didn't work). So I need a way to create them online, if you know one. I hope this is the...
  9. S

    Where do external photon terms go in Feynman diagram term ordering?

    I'm reading something which highlights the Feynman rules for QED, and it talks about what happens if you go along a fermionic line. For example this picture: http://wikipremed.com/image_science_archive_68/010601_68/170750_298px-ComptonScattering-u.svg_68.jpg According to these notes, there...
  10. G

    Are the Feynman Lectures the Right Choice for Self-Studying Physics?

    Hi, I live in the U.S. right now, but in a few months I'll be moving to another country. It will be much harder to get books like the Feynman lectures there, so I was wondering if I should get them now (or even at all). How good are they? Are they very difficult? How advanced should I be in...
  11. S

    What is a loop (in Feynman Diagrams)?

    Hey, I was wondering what exactly a loop is of this kind : I understand the initial & final four momentums to be the same and so there is no boundary on the possible allowed momentums in the loop. My professor said the loop is equal to (or can be modeled as) the self-interaction by...
  12. S

    Feynman Factors & Relativistic Scalar Propagator

    Hey again, I have a question on a couple of things related to feynman diagrams but also the relativistic scalar propagator term. First of all, this interaction: The cross represents a self-interaction via the mass and characterised by the term: -im^2, is this just some initial state...
  13. S

    Feynman diagrams and relativistic propagators

    Hey again, I have a question on a couple of things related to feynman diagrams but also the relativistic scalar propagator term. First of all, this interaction: The cross represents a self-interaction via the mass and characterised by the term: -im^2, is this just some initial state...
  14. H

    Feynman: Relativity of Magnetic and Electric Fields

    The diagrams aren't coming through on my system, but the text is readable: http://books.google.com/books?id=hlRhwGK40fgC&pg=SA13-PA6&lpg=SA13-PA6&#v=onepage&q&f=false First off, I'm pretty sure he re-uses ##\rho_\omicron## to mean different things at different points in the discussion...
  15. C

    Feynman Lectures - Anything similar for Mathematics?

    Last year I got volume 1-3 of the Feynman lectures but as a soon mathematics major I think it'd be appropriate to read more mathematics lectures (and more enjoyable). Is there anything similar I could ask for for my upcoming birthday? Thanks,
  16. H

    Why did Feynman use the incorrect version of the ideal gas law in eq. 45.13?

    I've noticed that Feynman appears to have incorrectly used the chemist's version of the ideal gas law. In eq. 39.23 he states it correctly: PV = NRT Pressure * Volume = Number of moles * Universal gas constant * Temperature Universal gas constant is R = N_{\omicron} k = Avogadro's...
  17. M

    QED, partial reflection, Feynman, FTL

    I would like to discuss partial reflection of the photons and how thickness of the material (let's say glass) affects reflection (originally from Feynman, QED). Let's say we have a glass 1m apart from the detector, and another glass 100m apart. The thickness of second glass affects probability...
  18. B

    Feynman Diagrams: Does Distance Affect Electromagnetic Interaction?

    Hello all . In feynman diagram horizontal direction is space . is that mean distance between particles ? is that means two electron must be near a certain distance to create a virtual photon ? Does one electron in Earth send electromagnetism force to one electron on moon by virtual photon ...
  19. H

    Is Figure 11-7 in Feynman's Lectures Incorrect?

    The figure 11-7 in Vol I of The Feynman Lectures appears incorrect to me. The second full paragraph explains exactly why it is incorrect. The caption should probably make it clear that the diagram represents the flawed depiction the author is warning against. Do others agree with this? If...
  20. K

    The Feynman Diagrams of Quantum Electrodynamics

    Hi all, I'm just getting started on particle physics and I have a few foolish :shy: questions about drawing feynman diagram. First, when do we draw the gauge bosons(such as W) vertically rather than horizontally through time? Second, can we always replace mediator photon by Z boson...
  21. I

    Feynman diagrams for Quantum Gravity

    Dear collegues, I want to share with you a little idea which permits to obtain (almost apparently) renormalizable Feynman diagrams for General Relativity. (See attached file) This idea exchanges renormalizability with non-locality. I'll vary fain if someone of you will try to calculate any...
  22. L

    Feynman Path Integral - All Possible Paths - Relativity Conflict?

    Hello I have not familiarised myself with the mathematics etc I merely have the conceptual idea that, for example, with the two slit experiement and electron is permitted to take "all possible paths" from the electron gun to the detector screen. The thought occurred (and as will all thoughts...
  23. W

    Feynman checkerboard as a model of discrete space-time

    Feynman checkerboard as a model of discrete space-time Back in 2006 Ed Hanna posted an interesting thread about this topic and I would really like to discuss it with him. Are you out there Ed - or does anyone know how to contact him? Thanks, John Wellings
  24. A

    Feynman diagramms for Photoelectric, Compton, Pair Production

    Hello to everyone! What are the feynman diagramms for the three basic photon interactions? Photelectric Compton(compton, Rayleigh and Thomsom scattering) Pair Production Thank you in advance!
  25. S

    Finding Quality Video Lectures: Feynman and Beyond

    if possible could you tag some good video lectures may be feymann or any other good source..thanks...!
  26. P

    Semester Project concerning Feynman Diagrams

    Hi there everyone. I'll try to keep this short. I'm currently a sophomore at a local college. I'm in Honors Calculus 1 and part of the honors course requires a research project at the end of the semester. I'm studying to be an ER Doctor/Particle Physicist, yes I know this will take some...
  27. E

    Are there any EE textbooks comparable to the renowned Feynman Lectures?

    Hello, I'm wondering if there are a series of books, analogous to the Feynman Lectures, for Electrical Engineering. The Feynman Lectures (as many of you know) are clear and concise, and nutshell a great deal of typical undergraduate study. A student can read these lectures from cover to...
  28. B

    How Do I Draw a Feynman Diagram for e+e- → VeVe?

    Feynman Diagrams! Please Help! Hi guys! I've been asked to draw a scattering and annihilation Feynman diagram for the following scenario: e+e- → VeVe (The second Ve is an anti-neutrino just couldn't figure how to put the bar on! :P I've tried it and I'm convinced the mediating...
  29. bohm2

    Relationship between Bohmian trajectories and Feynman paths ?

    Relationship between "Bohmian trajectories" and "Feynman paths"? Can someone summarize what (if any) relationship there is between these two? I've read that Bohmian trajectories are very different than Feynman paths but I've also come across papers suggesting that "Feynman method of summing...
  30. bcrowell

    Why exactly three lines at a Feynman vertex?

    The Feynman diagram you'd naively draw for a beta decay such as p\rightarrow n + e^++\bar{\nu} would have four lines joined at a vertex, but in reality there's a virtual W or Z involved, which makes it into two 3-vertices. Is there any fundamental reason why all the vertices in a field theory...
  31. J

    Help Finding Source of Feynman Quote

    Homework Statement I don't really know where to post this but I chose this section. I need help finding the source of this Feynman Quote "The probability of detecting a photon at any point is the sum of all the probabilities of the photon being detected at that point by any path" Homework...
  32. I

    Feynman diagram of electron and positron annihilation

    Hi all, I am learning Feynman diagrams, and I have a quick question: in diagrams such as the one for electron-positron annihilation (see http://en.wikipedia.org/wiki/Feynman_diagram#Electron-positron_annihilation_example) why is it that the line "in the middle" is that of an...
  33. E

    LaTeX Feynmf returns Feynman graph:\Delta , no diagram

    feynmf returns "Feynman graph:\Delta", no diagram I recently installed the package feynmf for drawing Feynman diagrams (or at least I think I did -- my MiKTex Package Manager says so). When I compile\documentclass{article} \usepackage{feynmf} \begin{document}\setlength{\unitlength}{1mm}...
  34. G

    Did Feynman unify special relativity with QM

    did feynman unify special relativity with QM or was it mostly a group effort and he just made some important contributions? did he make the decisive step just as leibniz and Newton made the decisive step with calculus? i watched a documentary about him and i couldn't get what his central claim...
  35. N

    Do the Feynman Lectures Include End-of-Chapter Problems?

    Are the Feynman lectures supposed to have problems in the end of the chapters? Because I am looking at some previews and it doesn't seem that they have problems to solve? I always thought that it would have challenging problems, perhaps I am confusing it with a different book.
  36. J

    Prerequisites to truly enjoy the Feynman Lectures?

    Hello all! I'm just out of high school and have got a few months before college begins. I think I'm fairly good in high school math, and now I've just started self-learning Single Variable Calculus (Calc I) from MIT OCW Scholar. I love Physics, and aim to be a physicist someday. I...
  37. T

    Number of weighted vacuum Feynman diagrams

    I didn't know where to put this, because it isn't a homework or coursework I have to do but just a thing I'm trying to understand. Anyway, I have attached the problem as an image. We have a scalar quartic lagrangian in d dimensions. It says that the number of vacuum Feynman diagrams, at a...
  38. maverick280857

    Gluon Scattering - Colored Feynman Rules for Yang Mills Theory

    Hi, I'm reading Appendix 1 of Section N2 (Gluon Scattering) in "Quantum Field Theory in a Nutshell" by Anthony Zee. The generators for SU(N) have the usual algebra [T^a, T^b] = i \epsilon^{a b c}T^c Suppose we adopt the following normalization \text{tr}(T^a T^b) = \frac{1}{2}\delta^{a b}...
  39. J

    Does Hamilton's principle follow from the Feynman formulation of QM?

    Do you think Hamilton's principle from classical mechanics can be deduced from Feynman's path integral in quantum mechanics? (We get across this question in another discussion: https://www.physicsforums.com/showthread.php?t=609087&page=5) Of course, there is a loose connection, since...
  40. N

    What is the highest order contribution in the Feynman diagram for K decay?

    Looking at, say, the decay K^+ \to \pi^+ + \pi^+ + \pi^- + \gamma, is it easy to say what the Feynman diagram is of highest contribution? I suppose it is not unique, but say we're satisfied with just one of highest order. Is there as it were a sort of flowchart one follows? For example, since...
  41. D

    Feynman Diagram: Simga+ -> p + gamma?

    Feynman Diagram: Simga+ --> p + gamma? Hi, Can anyone give me some indications as to how to draw the feynman diagram for the following decay? Ʃ+ → p + \gamma Should I consider the quark composition of the sigma first? Thanks a lot.
  42. E

    Reallllly dumb question about Feynman Parameters (and simplifying them)

    I know the generalized formula for Feynman parameters, my problem is in simplifying. What I mean is something like this: Take the simplest 3 parameter equation \frac{1}{ABC} = 2 \int_0^1 dx \int_0^1 dy \int_0^1 dz \frac{ \delta \left( 1-x-y-z \right)}{(xA+yB+zC)^3} And you can take this...
  43. S

    Feynman diagram tattoo suggestion

    Hi all After many months of contemplating, coming up with tattoo ideas, waiting a few months to see if I still like that idea, etc etc, I've settled on getting a Feynman diagram for many reasons, but having a but of trouble settling on one in particular. I've seen a few with the standard...
  44. M

    Feynman Diagram Vertices: What needs to be conserved?

    Hi, I'm taking introductory particle physics and this is related to the first couple of chapters in Griffiths. If I draw a Feynman diagram for a particular process, what conservation laws must hold at each vertex? Mainly looking at QED processs but as far as I can work out energy and momentum...
  45. N

    Should the Feynman graph for muon decay include an arrow on the W boson?

    Hello, The Feynman graph of muon decay is and I asked my professor if we could also write and he said no, because then out of nothingness an electron and an (anti)electron-neutrino would appear and send out a boson to the muon. However, I was not very convinced, so I wanted to double...
  46. C

    Feynman diagrams for spin 1/2 particles

    I think I have a pretty good handle on how scalar field scattering works in QFT, so now I'm trying to wrap my head around spin 1/2 particles, and I'm having a bit of trouble with it. For instance, in N + \phi \rightarrow N + \phi scattering, an application of the Feynman rules leads to an...
  47. H

    Draw Feynman Diagrams: e+e- to e+e-, μ+μ-, γ e-

    Homework Statement Draw the Feynman diagram vertex corresponding to the interaction Lint = eAμJμ, where Aμ is the electromagnetic field and e is the coupling constant. Draw all the Feynman diagrams in quantum electrodynamics to O(e2) describing the processes: (i) e+e- ----> e+e-, (ii)...
  48. H

    How Does Feynman Normalize CII in the Ammonia Molecule States?

    I'm trying to follow Feynman's explanation on page 9-3 of Volume 3 of The Feynman Lectures on Physics. I've attached a copy of the section in question. To normalize CII he notes that < II | II > = < II | 1 >< 1 | II > + < II | 2 >< 2 | II > = 1 I am not clear how he derives the conclusion...
  49. Z

    Feynman Lectures on Physics - Rotation in 2 dimensions

    This isn't really a 'problem', I'm just trying to follow Feynman's reasoning in section 18-2 of Volume 1 The Feynman Lectures on Physics. I've attached a png of the paragraph in question. I have 2 issues with this: 1. If the length OQ = OP, how can there be a right angle at P(x,y)? 2. I...
  50. M

    Basic question about Feynman Diagrams

    Can a vertex of a Feynman diagram have more than three particles going in or out from it? Assuming all other conservation laws are obeyed, of course. I haven't seen this being explicitly stated but all the Feynman vertices I have seen have three arms attached. Thank you.
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