Recent content by Maurice7510

  1. M

    Why does a SUSY Lagrangian only contain F and D terms?

    I'm reading a book on AdS/CFT by Ammon and Erdmenger and chapter 3 covers supersymmetry. This isn't my first look at SUSY but it's my first in depth look to really try to understand it, and when they talk about constructing a Lagrangian for ##\mathcal{N}=1## chiral superfields they write the...
  2. M

    I EoM via varying action - covariant derivative when integrate

    That makes a lot of sense, thanks. I was just thinking about it in a general sense and honestly just failed to consider that, but I now realize that was a foolish oversight. Thanks a lot!
  3. M

    I EoM via varying action - covariant derivative when integrate

    I just came across this and it was extremely useful but I'm having an issue when the number of indices on the two tensors is the same. For example, (in the integral) \begin{align*} \sqrt{g}A^{\mu}\nabla_{\nu}B^{\rho} &= \sqrt{g}A^{\mu}\partial_{\nu}B^{\rho} +...
  4. M

    Can anyone Recommend a good quantum gravity textbook?

    Thanks a lot! I was looking up the Kiefer book when I happened to come across one by Percacci, the latter of which covers a ton of extremely relevant topics from our research, so this is ideal for us
  5. M

    Can anyone Recommend a good quantum gravity textbook?

    I'm currently doing my thesis in QG and there's a distinct gap between where QFT and GR left off and QG begins, and as I'm sure most of you know, in a thesis you're sort of just thrown right into the deep end. As such, I was hoping someone could recommend a decent textbook that gives a solid...
  6. M

    A How to construct a spin-3/2 theory from the ground up

    I'll start by saying I'm posting this in Beyond the SM just because we have no elementary spin-3/2 particles in the SM as far as we know, though I was also considering posting it elsewhere. If you feel it's more appropriate in another area just let me know. As for the question itself, I'd like...
  7. M

    A Why are open strings vectors or scalars, or massive?

    I'm not sure how that would be the case though; the indices on the creation operator are ##i## (or ##a##) and ##-1##. The lower index is the state number (i.e. ##\alpha_{-1}## creates a one particle state) and the upper indicates indicate whether the BCs are NN or DD.
  8. M

    A Why are open strings vectors or scalars, or massive?

    In string theory, if we have NN BCs along ##X^i, i = 1, \ldots, n-1## and DD BCs along ##X^a, a = n, \ldots, 25## then you get, from ##\alpha^{i,a}_{-1}|0,p\rangle ##, ##n## massless vectors and ##24-n## massless scalars. I understand that for the first excited level, ##M^2=0## and so we have...
  9. M

    Complex integration, possibly branch cut integral

    Thanks a lot! The thing I'm trying to show in the end is that the integral is proportional to ##e^{-mx}##, which clearly this is.
  10. M

    Complex integration, possibly branch cut integral

    Yes, the factor of ##i## isincluded in the derivations I've seen, and I see now how it works. How might you recommend trying to solve this now? With Cauchy's integral formula, having $$\oint \frac{f(z)}{z-im}$$ would mean ##f(z)## would have a factor of ##\sqrt{z-im}## and would thus be zero...
  11. M

    Complex integration, possibly branch cut integral

    Now I've seen an extremely similar argument before (the same integral with just ##r^2+m^2## in the denominator is commonly approached) but they never include the ##Im##; perhaps this is just a result of physicists lacking proper mathematical rigour, but I've seen it in a few sources and was...
  12. M

    Complex integration, possibly branch cut integral

    Oh sorry, ##\theta## was from ##0## to ##\pi## and ##r## from ##0## to ##\infty##
  13. M

    Complex integration, possibly branch cut integral

    1. Homework Statement The integral I want to solve is $$ D(x) = \frac{-i}{8\pi^2}\int dr\,d\theta \frac{e^{-irx\cos\theta}}{\sqrt{r^2+m^2}}r^2\sin\theta$$ which I've reduced to $$ D(x) = \frac{-i}{4\pi x}\int dr \frac{r\sin(rx)}{\sqrt{r^2+m^2}} $$ by integrating over ##\theta##. However, I...
  14. M

    Zee, Quantum Field Theory in a Nutshell, problem 1.3.1

    I now realize I made a mistake in the spherical coordinate substitution, the integral should be $$ D(x) = \frac{-i}{8\pi^2} int dr\,d\theta \frac{e^{-irx\cos\theta}}{\sqrt{r^2+m^2}} r^2\sin\theta $$ The integral in ##\theta## is fairly straight forward at this point, and I got $$ D(x) =...
  15. M

    Zee, Quantum Field Theory in a Nutshell, problem 1.3.1

    That is curious, though I wrote exactly what he has in the book. Initially, we have $$ D(x) = -i \int \frac{d^3k}{(2\pi)^32\omega_k}[e^{-i(\omega_kt - \boldsymbol{k}\cdot\boldsymbol{k})}\theta(x^0)+e^{i(\omega_kt - \boldsymbol{k}\cdot\boldsymbol{k})}\theta(-x^0)] $$ which he reduces to the...
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