Schroeder Definition and 71 Threads

Schroeder is a North German (from Schröder) occupational name for a cloth cutter or tailor, from an agent derivative of Middle Low German schroden, schraden "to cut". The same term was occasionally used to denote a gristmiller as well as a shoemaker, whose work included cutting leather, and also a drayman, one who delivered beer and wine in bulk to customers; in some instances the surname may have been acquired in either of these senses. This name is widespread throughout central and eastern Europe which has been held by many notable people, including:

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  1. N

    Medical Student who misses physics

    G'day from Australia! I loved physics and maths in high school and I have been trying to teach myself some physics on the side whilst doing another course at university. So far, I have read and done problems from "Introduction to Thermal Physics (Schroeder)" [I got up to around 7.4] and...
  2. Antarres

    A Question about S(3) spontaneous symmetry breaking in Peskin & Schroeder

    In chapter 20 of Peskin&Schroeder about spontaneous symmetry breaking, he considers and example on page 696 of spontaneous symmetry breaking of SU(3) gauge group with generators taken in adjoint representation. Covariant derivative is defined with: $$D_\mu\phi_a = \partial\phi_a +...
  3. Diracobama2181

    I Ground State in Peskin and Schroeder

    In P&S, it is shown that $$e^{-iHT}\ket{0}=e^{-iH_{0}T}\ket{\Omega}\bra{\Omega}\ket{0}+\sum_{n\neq 0}e^{-iE_nT}\ket{n}\bra{n}\ket{0}$$. It is then claimed that by letting $$T\to (\infty(1-i\epsilon)) $$ that the other terms die off much quicker than $$e^{-iE_0T}$$, but my question is why is this...
  4. MathematicalPhysicist

    A mathematical derivation in Peskin and Schroeder on page 722.

    My attempt at solution is in the HW template, though this is not an HW question.
  5. MathematicalPhysicist

    A A possible mistake in Equations (18.204)-(18.205) in Peskin & Schroeder

    They write the following on page 646: Now, equation (17.17) reads: ##\alpha_s(Q) = \frac{2\pi}{b_0 \log(Q/\Lambda)}##, so if I plug ##\alpha_s(Q^2) = \frac{2\pi}{b_0 \log(Q^2/\Lambda)}## into Eq. (18.204) I get: ##\frac{a^f_n}{4b_0}\frac{1}{\log(Q^2/\Lambda)}M^-_{fn}##. Perhaps the...
  6. MathematicalPhysicist

    A A derivation in Peskin and Schroeder in chapter 18.

    They write on page 618: where for those who don't have the book at hand, I'll write the related equations: $$(18.94) \ \ \ \sigma(e^+ e^- \to \text{hadrons})=\frac{4\pi \alpha^2}{s} [ I am c^1(q^2)+Im c^{\bar{q}q}(q^2) \langle 0| m\bar{q}q|0\rangle+ $$ $$+Im c^{F^2}(q^2)\langle 0 |...
  7. W

    I Cross Section Formula in Peskin and Schroeder

    On page 105 of Peskin and Schroeder's book it says that the integral over ##d^2b## in the expression: $$d\sigma = \left(\Pi_f \frac{d^3 p_f}{(2\pi)^3}\frac{1}{2E_f}\right) \int d^2b\left(\Pi_{i=A,B} \int \frac{d^3 k_i}{(2\pi)^3}\frac{\phi_i(k_i)}{\sqrt{2E_i}} \int \frac{d^3...
  8. mdb71

    A Smart Algebra of Exp. on Pg 191 of Peskin & Schroeder

    Hi all, I have a problem working out the algebra of the following expression in Peskin & Schroeder in a smart way to give the result. It is on page 191, regarding the numerator of the vertex correction function. We want to get from the LHS to the RHS of the following expression...
  9. M

    ##CP^N## model in Peskin & Schroeder problem 13.3

    My naive attempt to expand the log was##log(k2+A2−λ)=log[(k2−λ)(1+A2(k2−λ))]=log(k2−λ)+log(1+A2(k2−λ))≈log(k2−λ)+A2(k2−λ)##but it did not help me so far since the second term vanishes. Can someone point me to the right direction?
  10. hamad12a

    I How Peskin & Schroeder simplified this horrible product of bilinears?

    P&S had calculated this expression almost explicitly, except that I didn't find a way to exchange the $$\nu \lambda$$ indices, but I'm sure the below identity is used, $$ \begin{aligned}\left(\overline{u}_{1 L} \overline{\sigma}^{\mu} \sigma^{\nu} \overline{\sigma}^{\lambda} u_{2...
  11. W

    A Questions from Peskin & Schroeder 5.5 about Compton Scattering

    Hi! Just a couple questions on the Compton scattering calculation in P&S. I feel like I'm missing something very simple here but can't quite figure out what it is. On page 166, the amplitude to be evaluated is $$ i\mathcal M = -ie^2 \epsilon_\mu(k)\epsilon^*_\nu(k^\prime) u_R^\dagger(p^\prime)...
  12. SebastianRM

    Intro to thermal Physics - D. V. Schroeder -Entropy question

    Hey guys, so I am reading this book and on pages 89-90, the author says: "Increasing temperature correspond to a decreasing slope on Entropy vs Energy graph", then a sample graph is provided, and both in that graph and in the numerical analysis given in page 87 the slope is observed to be an...
  13. L

    A Yang-Mills 3 boson Lagrangian term in Peskin and Schroeder

    Hi all, I'm not certain if this is the correct section of the forum for this thread but I'm trying to understand ghosts and BRST symmetry and my starting point is chapter 16 of Peskin and Schroeder where I've found a nagging issue. My issue is regarding the derivation of equation (16.6) on...
  14. almarpa

    Classical Complementary book for Schroeder's Thermal Physics

    Hello all. I am studying Thermal Physics from Schroeder's book. I really like this book, but the number of worked examples and solved problems is minimum. Could you please suggest me a complemetary book with worked examples and problems? The ideal book should be similar to Schroeder's, with the...
  15. MathematicalPhysicist

    The superficial degree of divergence in Peskin and Schroeder

    Homework Statement I have in the picture attached a screenshot from Peskin's textbook. I don't understand how did they get that for the two last diagrams that ##D=-2##. The question is from pages 316-317 of Peskin's textbook. Homework Equations $$D=4-N_{\gamma}-3/2N_e$$ where ##N_e##=number of...
  16. S

    I How to Calculate Page 14 of Peskin Schroeder without Getting Stuck?

    Hi Everybody, I am trying to do the calculation of Peskin Schroeder page 14, namely the first block of equations. The author moves from: U(t) = \frac{1}{2 \pi^3} \int d^3p e^{-i(p^2/2m)t} e^{ip \cdot (x-x_0)}. to U(t) = (\frac{m}{2 \pi i t})^{3/2} e^{im(x-x_0)^2/2t}. I guess the way to go...
  17. diegzumillo

    A Charge conjugation in Peskin and Schroeder

    Hey there I'm trying to reconstruct the entire table of all Dirac bilinears under C, P, T and CPT transformations of page 71 and hit a wall on charge conjugation. It's a computational problem, really. Here's a specific problem: Equation 3.145 we have $$-i\gamma ^2 \left( \psi ^{\dagger...
  18. Romanopoulos Stelios

    Differentiation of unitary operator U(t,t') in Peskin and Schroeder

    How the authors came to the conclusion (eq. 4.25) that $$ U(t,t')=e^{iH_0(t-t_0)} e^{-iH(t-t')} e^{-iH_0(t'-t_0)} $$
  19. qqbar

    What Explains the Extra Factor of 2 in Peskin and Schroeder's Eq. 18.84?

    Homework Statement So I am self-studying the book of Peskin&Schroeder, and there is something I don't understand on page 616. In eq. 18.80, there is a numerical factor of ½ and going from e2 to α will introduce a factor 4π when proceeding to eq. 18.84. But then there should be a numerical...
  20. S

    Peskin & Schroeder - page 5 - Computation of ##\mathcal{M}##

    The following is taken from page 5 of Peskin and Schroeder. It talks about the computation of ##\mathcal{M}## for the annihilation reaction ##e^{+}e^{-}\rightarrow \mu^{+}\mu^{-}##. Even for this simplest of QED processes, the exact expression for ##\mathcal{M}## is not known. Actually this...
  21. S

    Peskin and Schroeder - page 4 - spin and cross section

    In chapter 1 of Peskin and Schroeder, the reaction ##e^{+}e^{-}\rightarrow \mu^{+}\mu^{-}## is studied in detail. The related following paragraph is taken from page 4 of Peskin and Schroeder: Both the electron and the muon have spin ##1/2##, so their spin orientations must be specified. It is...
  22. S

    Peskin and Schroeder - page 4 - choice of notation

    In page 4, Peskin and Schroeder has the following diagram: The diagram shows the collision of an electron beam and a positron beam to produce a ##\mu^{+}## beam a ##\mu^{-}## beam. My question is this: The electron and positron beams are shown to have momenta ##\textbf{p}## and...
  23. S

    How Does the Angular Momentum Commutator Derive the Lorentz Algebra?

    In page 39, Peskin and Schroeder write that (3.15) ##{\bf{J}}={\bf{x}} \times{\bf{p}}= {\bf{x}}\times(-i \nabla) ## can be used to derive the Lorentz algebra (3.12) for the rotation group: ##[J^{i},J^{j}] = i \epsilon^{ijk}J^{k}##. I am trying to prove it. Here's my attempt. Can you please...
  24. S

    Peskin and Schroeder - Derivation of equation (2.45)

    I'm having trouble deriving equation (2.45) on page 25. In particular, in the derivation of ##i\frac{\partial}{\partial t}\pi({\bf{x}},t) = -i(-\nabla^{2}+m^{2}) \phi({\bf{x}},t)##, I need to show that ##\frac{1}{2}\pi({\bf{x}},t) \phi({\bf{x'}},t)(-\nabla^{2}+m^{2}) \phi({\bf{x'}},t) -...
  25. N

    S matrix Unitarity Proof, pg 298 Peskin Schroeder

    I have a question regarding a derivation in Peskin and Schroeder's QFT book. On page 298, he is discussing a method for defining a gauge invariant S matrix. He does this by defining projection operators ##P_0## that project general particle states into gauge invariant states, and then defining...
  26. R

    Contour Integral from Peskin & Schroeder Intro to QFT

    1. I'm having some trouble with some of the contour integrals covered in Chapter 2 of Peskin & Schroeder's Intro to QTF. I'm not so much as looking for answers to the integral (in fact, the answers are given in the textbook), but I was hoping someone could point me to some resources to use to...
  27. MathematicalPhysicist

    Questions from Peskin and Schroeder

    On page 42 of Peskin, at the bottom they say that the next transformation should follow: ##[i\gamma^\mu\partial_\mu - m ]\psi (x) \rightarrow [i\gamma^\mu(\Lambda^{-1})^\nu_\mu \partial_\nu - m ] \Lambda_{1/2} \psi (\Lambda^{-1}x)## But why does the factor ##\Lambda_{1/2}## appear there...
  28. N

    Schroeder: Intro to thermal physics, Diff. between editions?

    Hi, I'm facing a slight problem with getting a good version of the Schroeder: Introduction to thermal physics. According to my lecturer the newest 2013 international edition by Pearson (ISBN: 9781292026213) is not recommended, as it lacks some aspects. And anyway the course is built around the...
  29. H

    Question on peskin and schroeder

    If you go to page 20 and 21 where the Fourier expansion of the klein-gordon field operator is derived, you'll see equation (2.27). Now there are some small details of this whole calculation that I'm confused about. I followed all the way through to (2.25), but here I feel a bit weird. Isn't he...
  30. ChrisVer

    Peskin & Schroeder Problem 4.1

    I am having some problems in evaluating the current problem's question (b)... I have reached the point (writing only the term which I have problem with): A_{3}= - \frac{1}{2} \int_{t_{0}}^{t} dt' dt'' \int d^{3}x \int d^{3}y j(x,t') j(y,t'') D_{F}(x-y) So for some unknown reasons, I cannot...
  31. C

    Peskin and Schroeder derivation of Klein-Gordon propagator

    In page 30 of book "An introduction to quantum field theory" by Peskin and Schroeder in the derivation of Klein-Gordon propagator, why p^0=-E_p in the second step in equation (2.54). and why change "ip(x-y)" to "-ip(x-y)"? I thought a lot time, but get no idea. Thank you for your giving me an...
  32. L

    How accessible is the Peskin and Schroeder textbook?

    **Please can an administrator move this to the "Maths and Physics Learning Materials" section- I can't post there for some reason. Thank you!** Hello, I am interested in learning some more technical Quantum Mechanics, and was wondering how accessible the Peskin and Schroeder textbook is as...
  33. N

    (Peskin and Schroeder) Numerator of vertex correction

    Hi I am studying qft with worldwidely used text, written by Peskin and Schroeder, An introduction to qft. I have trouble with the calculation of thr numerator on pp. 192. I got additional term ## 2m(z-xy)(mγ^μ - p^μ) ## between spinors, which seems not vanishing. Is there any idea to treat this...
  34. S

    Peskin Schroeder page 30 eq 2.54

    Hello Everybody, I am trying to get the second line of 2.54 from the last line; I want to get: \int \frac{d^3p}{{2 \pi}^3} \{ \frac{1}{2 E_\vec{p}} e^{-ip \cdot (x-y) }|_{p^0 = E_\vec{p}} + \frac{1}{-2 E_\vec{p}} e^{-ip \cdot (x-y) }|_{p^0 = -E_\vec{p}} \}, from \int...
  35. N

    Polarization of photon-Peskin and Schroeder

    Hi, I am currently studying quantum field theory with worldwidely used text written by Peskin and Schroeder. On page 165 of that text it says, " the amplitude vanishes unless the final photon is right-handed." But I cannot figure out how it works. With ε = (0,1,i,0), I get same expression...
  36. C

    Renormalization procedure (Peskin and Schroeder)

    In Peskin and Schroeder at page 323 second paragraph the author state 'To obtain finite results for an amplitude involving divergent diagrams, we have so far used the following procedure: Compute the diagrams using a regulator to obtain an expression that depends on the bare mass (m0), the...
  37. C

    Fourier transform of integration measure (Peskin and Schroeder)

    At page 285 in Peskin and Schroeder's Introduction to quantum field theory the author defines the integration measure D\phi = \Pi_i d\phi(x_i) where space-time is being discretised into a square lattice of volume L^4. He proceeds by Fourier-transforming \phi(k_n) = \frac{1}{V} \sum_n e^{-i...
  38. C

    Splitting up of functional integral (Peskin and Schroeder)

    I'm reading about path integrals in Peskin and Schroeder's Introduction to Quantum field theory and there is a few things in the text which I find puzzling. At page 283 in the section about correlation functions we are considering the object (equation 9.15) \int D\phi(x) \phi(x_1) \phi(x_2)...
  39. C

    Peskin & Schroeder QFT Born Approximation reference.

    I'm currently teaching myself some QFT trough Peskin and Schroeders Introduction to QFT and I've noticed that in several arguments they rely on appealing to the Born approximation of non-relativistic QM scattering theory. For example on page 121 equation (4.125) they appeal to the scattering...
  40. V

    Differential cross sections in Peskin & Schroeder

    I'm a bit confused by something Peskin & Schroeder say about differential cross sections. In my printing, this is on page 101 in the paragraph preceding the one that contains eq. 4.62: "In the simplest case, where there are only two final-state particles, this leaves only two unconstrained...
  41. N

    Peskin & Schroeder p. 285, change of variables integration measure

    I had a question about about the integration measure for the path integral after a unitary change of variables. First they consider a 4D spacetime lattice with volume L^4. The measure is \mathcal{D}\phi = \prod_i d\phi(x_i) They expand the field variables in a Fourier series...
  42. I

    Integration question in Peskin and Schroeder

    Hi all, I'm stuck with proving the last step of (2.51) in Peskin and Schroeder: $$\begin{align} D(x-y) &= \frac{1}{4\pi^2}\int^\infty_m dE \sqrt{E^2 - m^2}e^{-iEt}\\ & \approx_{t \to \infty}\ \ e^{-imt}\end{align}$$ I've read on another post that the solution is to use the method of...
  43. I

    Polarization vector in Peskin & Schroeder QFT

    Hi all, A friend and I are working through Peskin and Schroeder, and we're both stumped with only the fourth equation! The interaction in question is e^+ + e^- \to \mu^+ + \mu^- with a virtual photon as the inner branch. P&S state that \mathcal{M}\propto \langle \mu^+\mu^- | H_I | \gamma...
  44. J

    Factor in equation (3.49) of Peskin and Schroeder

    My question concerns the 1/2 factor in the exponential of Eq. (3.49) of Peskin and Schroeder. This equation concerns the Lorentz boost transformation of a spinor along the z-axis (or 3-direction). According to Eq. (3.26): S^{03} = -\frac{i}{2}\begin{bmatrix}\sigma^3 & 0 \\0 &...
  45. T

    Fick's Law (Schroeder, Thermal Physics Page 47)

    This isn't a HW problem - I am just having a hard time following one of his examples. On page 47 near Eq. 1.71 he says "As a quick example, consider a drop of food coloring added to a glass of water. Imagine that the dye has already spread uniformly through half of the glass. How long would...
  46. D

    Pesking & Schroeder Eqn 3.18 (Lorentz algebra)

    I am trying to show that (for 4x4 matrices) the representation given by equation 3.18 (Peskin and Schroeder, page 39): (J^{\mu\nu})_{\alpha\beta} =i(\delta^{\mu}_{\alpha}\delta^{\nu}_{\beta}-\delta^{\mu}_{\beta}\delta^{\nu}_{\alpha}) implies the commutation relations in 3.17...
  47. P

    Another doubt in Peskin Schroeder Sec 4.2

    This doubt is about a text in Peskin Schroeder Pg 86. I reproduce it here. -------------------------------- U(t,t') satisfies the same differential equation (4.18), i \frac{\partial}{\partial t} U(t,t') = H_I(t) U(t,t') but now with the initial condition U=1 for t=t'. From this...
  48. I

    Peskin Schroeder Enigmatic Equation

    Hi, I am learning QFT in the Peskin/Schroeder book and I found 4.56 on page 98 really weird, it is: \rho_{vaccum\: energy\: density} = \frac{i\sum_{all\: disconnected\: diagramms}amplitude}{(2\pi)^4\delta^{(4)}(0)} The authors do not comment really this result, but could someone tell me at...
  49. J

    How Do You Quantize Spinor Theory in Quantum Field Theory?

    Homework Statement Problem 3.4e of Peskin & Schroeder Introduction to Quantum Field Theory. Quantize the spinor theory of item (a) of this exercise, where the spinor \chi is the first two components of the Dirac spinor (\psi_L). Find a Hermitean Hamiltonian and the correct...
  50. T

    QED: Vertex renormalisation; Please have Peskin and Schroeder book handy

    Hi guys, I have a question regarding a point in the QFT book of peskin and schroeder. Iv been working through renormalisation in QED, The 2-point corrections are simple enough, however in this book the 3-point function is a little more involved and I have some issues. Essentially id to...
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