Recent content by Scott1137

Years ago after reading Ch. 12 of Peskin and Schroeder (and the analogous discussion in Zee), I thought I fully understood the modern Wilsonian view of renormalization, and how it explains why non-renormalizable field theories still have meaning/predictive power at energies well below the...

Thanks. Nevertheless, this reasoning makes me very uneasy. This seems to say that the Z-factors are 1 for free field theory, but discontinuously jump to 0 with an interacting theory, even if the coupling in the interacting theory is arbitrarily small. This conflicts with my experience with...

Ok, sorry to be so dense, but I don't understand your statement that it is 1/Z and not Z that diverges. This seems to be in conflict with what's in Srednicki and every other QFT book I've glanced at. To 1-loop order, in Eq. 14.37 Srednicki finds (in phi**3 theory in d= 6-ε spacetime)...

Sorry Bill_K, I don't follow. Let me rephrase my question in case the original wasn't clear. In problem 13.1, we use non-perturbative arguments to derive a sum rule that relates the field-strength renormalization $Z_{\phi}$ to the spectral density $\rho(s)$: \begin{equation} Z_{\phi} =...

Hi- I've just completed problem 13.1 in Srednicki in which he tells us to relate the field-strength renormalization $Z_{\phi}$ to the spectral density $\rho(s)$ that appears in the Lehmann representation of the exact propagator. It seems straightforward-- I follow the hint, insert unity using...