Peskin Definition and 115 Threads

Dear all, While I was reading chap2 of Peskin, I got some questions. (1) The vanishment of the commutator of fields [\phi(x),\phi(y)]=0 means that the measurements at x and y do not interfere at all. Is this a postulate? Is this the so-called micro-causality? (2) How Peskin deform the...

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...

Dear PF, I have one question form Peskin Schroeder...could you pls help me It is very simple question... Since I don't know how to write formulas here I put my question in attachment. Thank you very much.

Sorry for bothering... How does righthand side of formula 5.94 is derived from its left handside after some approximation? Probably it is very simple question but I could't get that expression:confused: Thank u very much

I'm still pretty new to QFT, so forgive me if I have made a ridiculous mistake. I've been learning QFT from Peskin and Schroeder mostly but decided to read Ryder recently and I have just come across an amazing result (in my opinion) in Chapter 3. Ryder basically shows that the electromagnetic...

Hi, This is regarding showing, in ch.7, around p.220, that the Pauli Vilars regularization technique is consistent with the ward takahashi identity. I cannot get the following to work: I add eq. 7.31 to eq. 7.32 and do not get zero. I get alpha over 4 pi. (I am left with integral ( 1...

Hi I'm planning on studying quantum field theory, but I can't choose which book I should buy. I've heard great opinions of both, that's making my decision so hard Peskin's Introduction to Quantum Field Theory https://www.amazon.com/gp/product/0201503972/?tag=pfamazon01-20 or Mandl...

Hi, I am stuck on a step Peskin & Schroeder give in their proof of Wick's Theorem (Intro to Quantum Field Theory, p 90). In the middle of the page when they consider the term with no contraction, it seems like in between the 1st and 2nd lines they somehow factor out the normal ordering...

Gentlemen, Could you help me please, I am sure it is not even worthy of your attention, but anyway... In Peskin, Schroeder - from expresion <0|\phi(x)\phi(y)|0> survives <0|a_p a_q^\dag|0> so it creates one-particle state |q> at position y and another one-particle state | p> at postion...

Can someone tell me what the two commutators in (2.30) stand for? It has to be Dirac delta functions, but which one exactly? thank you

would someone mind opening his/her beloved P&S and help me out.. on p.20 it says if we expand the classical Klein-Gordon field in Fourier (momentum) space, we arrive at equation 2.21...why is that? gracias

Hi, I'm stuck with problem 10.3 from Peskin's QFT book. I'm trying to evaluate the 2-loop sunset diagram in massless phi^4 theory however I keep running into trouble. I'm trying to use standard feynman parameter + dimensional regularisation techniques however i keep getting stuck when it...

Greetings--I have a few questions from An Introduction to Quantum Field Theory by Peskin and Schroeder. Note: I'm not sure how to construct the contraction symbol using \LaTeX, so instead I will use the following cumbersome convention: \overbrace{\psi(x)\overline{\psi(y)}}=S_F(x-y), they...

I am unsure if this is the proper forum for this, since it is not actually homework... but here goes anyway. I am trying to Prove Peskin and Schroeder equation 2.33( the second equal sign) P=-\int d^3 x \pi (x) \nabla \phi (x) = \int \frac{d^3 x}{(2 \pi)^3} p a^{\dagger}_p a_p so...

Hello all, Just wondering if Peskin and Schroeder is a good first time QFT book? If so, what would be a good book to supplement it with? Cheers, Norm