Recent content by Phymath

The question is more of a mathematical question then one about physics in the attached file between equations 6 and 7 it says "integration over the modes" i don't know how they go from the integration measure \int D\phi \rightarrow \int D\phi_1 D\phi_2...D\phi_N any advice would be...

ok so i think this is resolved for now, Now to start a new thread: what the hell is this Faddeev-Popov determinant?! ahhh lol

Note that in the google version the diagrams of eq 10.20 are the corrections to the coupling const \lambda not corrections to the propagator, the propagator only has diagrams of 1 line and 1 line with loops in them (making 2 external lines) such as ------ + ----()---- , the () is a loop...

I did the Srednicki calculation its very straight forward and works I suggest doing it, however it brought me a new question, when do I use the "crossed" Feynman diagrams? i mean by crossed the physical ones such as -----k-->--X----k-->-- = -i(A k^2 + B m^2) I don't know when i should use...

good to see someone else finds this section of Zee's book lacking. While I haven't finished the entire calculation the first reference to Srednicki does offer an example calculation of the mass renormalization using the physical pert theory. Mark Srednicki does generously offer his...

so...still how might i calculate the propagator out to first order using the physical theory?

<0|\phi(x)|0> = \frac{1}{Z(J=0)}\int D\phi \phi(x) e^{\frac{i}{2}\int (\partial \phi^2 - m^2 \phi^2) - \frac{\lambda}{4!}\phi^4} <0|\phi(x)|0> \approx \frac{1}{Z(J=0)}\int D\phi \phi(x)(1-\frac{ i \lambda}{4!}\int\frac{\delta^4}{\delta J(w)^4}d^4w) e^{\frac{i}{2}\int (\partial \phi^2 - m^2...

I'm using many books, Mainly "Quantum Field Theory in a NutShell" by Anthony Zee. I enjoy the focus on physics rather than math presented in this book, however I am also using Peskin & Schroeder for more mathematical rigor. I have access to Srednicki as well and will look at the reference you...

I'm reading a QFT text right now and to fully understand the physical perturbation theory method I would like anyone to suggest a refrence or supply an example of a calculation using the physical perturbation theory: As an example to start a discussion consider. L = \frac{1}{2}((\partial...

In a book about group theory in physics (Wu-Ki Tung) he is using the Euler angle representation of a rotation I'm unsure how he gets the following results... R(\alpha,\beta,\gamma) = e^{-i \alpha J_z}e^{-i \beta J_y}e^{-i \gamma J_z} he writes R^{-1} J_3 R = -sin \beta (J_+ e^{i...

I'm having difficulty with the D^{l}(\theta) representation of 3D rotations what do the mean i suppose one you construct it for l = 1 you get the general rotation Euler matrix for 3-d Space, but what do the l = other integers or half integers mean physically? is the D matrices the...

thats a lot of work when you can just do the general Ehrenfest Thrm for O some operator \frac{d <O>}{dt} = \frac{\partial}{\partial t} <\psi|O|\psi> = <\dot{\psi}|O|\psi> + <\psi|O|\dot{\psi}>+<\psi|\dot{O}|\psi> -i |\dot{\psi}> = H |\psi> \frac{d <O>}{dt} = i <[H,O]> + <\frac{\partial...

Homework Statement reading shankar he develops the measurement of angular momentum by discussing rotation state vectors in 3-D by the angle-and-axis parameterization so he creates these generators of rotation matrices and says these are what we use to measure angular momentum in analogy to...

ok I used the SO(3) matrix instead of SO(2) and that does give back the same matrix however if i still do it in 3-d i don't get the same matrix back R(d\theta) = I - i d\theta J \rightarrow J = \[ \left( \begin{array}{ccc} 0 & -i & 0 \\ i & 0 & 0 \\ 0 & 0 & 0...

Homework Statement I'm trying to see the relation of the rotation of a vector in a plane to the generator of rotations... I want to see how e^{-i \theta J} the rotation representation gives you the same result as acting on any vector with the rotation matrix say with the z direction fixed. \[...