Diagrams Definition and 659 Threads

I have drawn five connected diagrams that arise in ##\phi^4## theory. I was wondering if the symmetry factors I have for each of them are correct and if I have missed any graphs. I only want to consider the case of ##V=3, ## with ## J=0,...4## in turn. (V: number of vertices which i denoted by a...

Hello everyone, I've been wondering for a while how is it possible to determine which decays are possible from a particle or, given a decay be sure that the given decay is possible and hence draw a Feynman diagram of it. I know I have to take into account conservation charge, energy...

Homework Statement A system , which comprises three components (A , B and C ) , the system fails if the first component ( A) has failed or if the other two fail simultaneously. It will be assumed that all components operate independently. Question: Choose from the following diagrams that best...

When you look up a ray diagram for a telescope you get the following: From reading my book it seems clear that the objective lens forms and image on the focal plane. This then serves as an image for the eyepiece. Since the focal length of the eyepiece at the focal length of the objective lens...

I am talking about perturbative quantum field theory. When calculating elements of correlation functions(which then I use to calculate S-matrix elements) one always comes up with connected and disconnected diagrams. These disconnected diagrams are usually dropped from the calculation and I...

In my opinion, using Venn diagrams, or set theory in general, to help aspiring SQL programmers (yes, SQL is a programming language) understand joins causes nothing but confusion for literal-, logical-thinking persons like myself. Allow me to explain my opinion. Venn diagrams have always been...

How would I use a truth table to show that the statement p v (q ^ r) is equivalent to (p v q) ^ (p v r) or design a venn diagram for this. and show that this statement is not equivalent to (p v q) ^ r.

Hi all, I am given a data table, with dependencies. Can I use MS MySQL workbench to draw the associated dependency diagram? Thanks.

Hello, Can u please explain how to convert a PV diagram to a TS diagram in thermodynamics. Thanks in advance

I am trying to learn about Feynman diagrams and am confused by some of the notation. In particular, what do matrices, in particular the Dirac adjoint, have to do with Feynman propogators and why are they in imaginary terms?

Homework Statement In the image uploaded below, a boxed shaped object is shown. It is floating in water so the forces that act on it are buoyancy and gravity. The first and the last compartments are filled with evenly distributed weight. The middle 2 compartments are empty. Specifics are...

For quartic scalar field theory these are some of the lowest order diagrams (taken from the solutions to 9.2 srednicki). I'm wondering if someone can give me an intuition of how to actually calculate them. What I'm thinking is that vertices are $$\int \frac{d^{4}x}{(2\pi)^{4}}$$ and for the...

Could someone please tell me the difference between tree diagrams and loop diagrams? If I'm thinking correctly tree diagrams are before contracting? Also how do vacuum diagrams fit into the picture? Thanks!

On page 60 of srednicki (72 for online version) for the $$\phi^{3}$$ interaction for scalar fields he defines $$Z_{1}(J) \propto exp\left[\frac{i}{6}Z_{g}g\int d^{4}x(\frac{1}{i}\frac{\delta}{\delta J})^{3}\right]Z_0(J)$$ Where does this come from? I.e for the quartic interaction does this...

Hi!, I am studying for an introductory course in QED and Feynman Diagrams. Everything we see is like a first order approach and I am having some trouble understanding antiparticles in Feynman Diagrams: Why is it that we put an antiparticle that is leaving as if it is entering the interaction...

I'm trying to draw Feynman diagrams with the feynarts.sty package for LaTex. The problem is that if I write the following code \begin{feynartspicture}(150,150)(1,1) \FADiagram{} \FAProp(0.,10.)(6.,10.)(0.,){/Straight}{0} \FALabel(3.,9.18)[t]{$1$}...

Homework Statement This is just an example/solution to a timing diagram/gate delay for the circuit of logic gates. I am reading ahead of the chapter on gate delays & time diagrams, however, the book doesn't provide as much information. I am unsure how the solution came about in drawing their...

Homework Statement Compute the matrix element for the scattering process \phi \phi \to \phi \phi Homework Equations The Lagrangian is given by L = \frac{1}{2} \partial_{\mu} \phi \partial^{\mu} \phi + \frac{\alpha}{2} \phi \partial_{\mu} \phi \partial^{\mu} \phi + \frac{\beta}{2} \phi^2...

I have a simple question. I know that the objects that we work with in introductory physics are point particles. Thus, say we have a picture frame that is put on a wall. There is a wire holding it up, where the wire is attached to the top right and the top left corners of the frame. The passes...

I have completed the questions in the attachment I just need someone to tell me if they are correct and I'm doing them right. Thanks.

Dear Forum Memebrs, Could you please advise if it is possible to think that in some instances the flow of fluid in P&ID diagram is similar to the flow of electrical current in circuit boards: in order to have an electric current you have to have a potential difference across two points (which...

Homework Statement Suppose I've got a static mass on a downward plane. (For instance a car on a drive way). How would you set up this free body diagram? Homework Equations F = f1+f2...etc The Attempt at a Solution My preference is A, but I've seen it displayed in examples in my book as B...

Homework Statement Force by uniform loading = 20(5) = 100kN Vertical component of the uniform loading = 20(5)(3/5) = 60kN Horizontal component of the loading = 20(5)(4/5) = 80kN vertical reaction at roller support = Vr vertical reaction at pin support = Vp Homework Equations Fx=0, Fy=0...

Hi, I saw at the lecture something that called Cobweb diagram/plot and it was given without too much explanation. We were working on recursive sequences(Math major, first semester). The sequence was \frac{1}{2-\frac{1}{2-...}} I tried to find an explanation to this diagram; why did we choose...

Hi, I was wondering if there is code already available to draw group lattice diagrams if I already know what the subgroup structure of the group and its subgroups are. For example, it's easy to determine the subgroup lattice for cyclic groups simply using divisors via Lagrange's Theorem...

Homework Statement Three charged particles are placed at each of three corners of an equilateral triangle whose sides are of length 2.7 cm . Two of the particles have a negative charge: q1 = -6.0 nC and q2 = -12.0 nC. The remaining particle has a positive charge, q3= 8.0 nC . What is the net...

¿How is possible deduce the Lagrangian of the fields of a theory knowing only his Feynman Diagrams?

Homework Statement Let A and B be two events such that P(A) = 0.4, P(B) = 0.7, P(A∪B) = 0.9 Find P((A^c) - B) 2. Homework Equations I can't think of any relevant equations except maybe the Inclusion Exclusion property. P(A∪B) = P(A) + P(B) - P(A∩B) This leads us to another thing P(A∩B^c)...

I am looking for a short pedagogical introduction to Young-tableaux and weight diagrams and the relationship between them, which contains many detailled and worked out examples of how these methods are applied in physics, such as in the context of the standard model and beyond for example. I am...

I am reading the book tilted "quantum field theory in a nutshell(second version)" by A.Zee. On the page 45, for example there is a term \frac{1}{m^2}λJ^4. The question is that how to related it to the Figure 1.7.1. or that, How can I draw the three diagrams in Figure 1.7.1 from the term...

I have some confusion over some diagrams involved in proton decays in SU(5). I've seen a few like this that look weird to me. Here is one I found where the colored Higgs triplet does the job: Straight away I don't know what to make of this because I've only ever seen diagrams where fermions are...

Hi, I once considered myself enough to be decent enough to solve some problems but lately I'm thinking to revisit and start solving problems again. I would like to know whether there is a book good which has problems (starting from basic to tough ones) for practicing free body diagrams. The book...

Hi Pfs Is there a method to draw a Penrose diagram when the spacetime metric is known? Thanks.

Hi there, In paper as : http://authors.library.caltech.edu/8947/1/GREprd07.pdf I don't understand the colour factor associated with two gluons and single octet scalar as the first Feynman diagram in fig. 3 ? In eq. 27, this colour factor is given by ## (d^{abc})^2 ## .. so, how did this come...

I've been learning about Greens functions. I'm familiar with how to find them for different differential operators and situations but far from fully understanding them. We were shown in lecture how they can be used to obtain a perturbation series, leading to Feynman diagrams which represent...

Good morning, I'm looking at some logic diagrams for relays and have encountered something that I've never seen before. I haven't looked on the internet extensively since I thought the folks here at the forums would be able to answer my question more quickly. My experience with logic is...

This is a little toy I put together that I thought might be of interest: http://ibises.org.uk/Minkowski.html It's an interactive Minkowski diagram. You can add events and connect them up with straight-line paths, then Lorentz boost either to a specified velocity or to the rest frame of a...

Homework Statement 2 masses, m1 and m2 are connected by a cord and placed on a frictionless table as shown in the diagram below. m1 slides on the frictionless table while m2 is hanging from a light frictionless pulley. What would be the mass of the hanging mass m2 if we know that the tension in...

Exchange Particles are to show the transfer of (for example) +/- charge to the other side so the charges balance. But I don't understand... Beta plus decay: p → n + e+ + νe. This is just an example, the Feynman diagram shows a W+ boson transferring the positive charge to the right hand side...

Homework Statement Homework Equations None. The Attempt at a Solution This is the final part of a past exam question. I've got through the first parts and can (thanks to a separate question I asked here) read the phase diagrams and find melting points etc. However now it's asking for...

Okay guys so I the lagrangian \mathcal{L}=\dfrac{1}{2}\left( \partial_{\mu}\phi\partial^{\mu}\phi-m^{2}\phi^{2} \right)+\dfrac{\lambda}{4!}:\phi(x)^{4}: where \phi(x) is a real scalar field. I want to know how you can draw the self-energy diagrams at order \lambda and \lambda^{2} for a 2 => 2...

When I study about the transformation of coordinates, especially while defining gradient, curl, divergence and other vector integral theorem in different co-ordinate system, a concept called metric is defined and it is said to used for transform these operators in different co-ordinates, it is...

Homework Statement A cylindrical container is sealed with a movable piston and contains 0.200 mol of oxygen. The initial pressure is 2.5 × 10^5 Pa and the initial temperature is 77◦C. The value of the ideal gas constant is R = 8.315J/mol · K. The oxygen, which can be approximated as an ideal...

Homework Statement (a) e- + e+ -> e- + e+ (b) e- + e- -> e- + e- c) e- + e- -> e- + e- + u+ + u- d) y -> e+ + e- e) y + y -> y + y Homework EquationsThe Attempt at a Solution Part (a)[/B] Part (b) Part (c) Part (d) Part (e) Not sure what to do with this, since usually the...

Hey guys, I need help with conserving momentum at these vertices (this is Bhabha scattering): So in Diagram (a), the first vertext to the left. The incoming momenta are p_{1}+p_{2}. The outgoing momentum I'll call it p. So...shouldnt I have p_{1}+p_{2}=p? Furthermore, is the propagator...

Homework Statement Complete the timing diagram for the following circuit: Homework EquationsThe Attempt at a Solution So I was doing some pre-midterm studying, and I was slightly confused with the operation of this circuit. I think part of the solution provided is incorrect, but I'm not...

Homework Statement Hello, My thermodynamics professor gave us homework to plot 3 lines of constant temperature on a PV diagram in excel and 3 lines of constant pressure on a TV diagram. I have no clue how to do this and was wondering if someone could help me Homework Equations He gave us the...

Homework Statement (a) Find energy of incoming beam that creates highest cross section (b) What are the differences in the two reactions, using quark diagrams? (c) What would the peaks of the two reactions be like? Homework EquationsThe Attempt at a Solution Part(a) [/B] Cross section is...

I am absolutely clueless when it comes to drawing free body diagrams. I think I understand the concepts but as soon as I see an unfamiliar system I have no idea what goes where. Are there any resourcess that provide a large number of practice problems (with solutions) for drawing free body...

Homework Statement At a construction site, a small crane is raising two boxes of nails on a plank to the roof. One box has already been opened and is half full, while the other box is new. The boxes, including the nails, weigh 10kg and 20kg, respectively, and are both the same size. If the...