933 reputation
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location New England
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visits member for 3 years, 4 months
seen May 11 at 2:05

PhD student.


Jul
2
awarded  Curious
Mar
19
awarded  Yearling
Dec
29
awarded  Taxonomist
Mar
19
awarded  Yearling
Jul
29
awarded  Popular Question
Mar
19
awarded  Yearling
Mar
4
comment Instantons and Borel Resummation
@SidiousLord: good point. But I'm more interested in seeing an application in a specific problem, which Weinberg's book hasn't done.
Mar
4
asked Instantons and Borel Resummation
Jan
15
comment How to prove equivalence of RG flow of QFT coupling constant and diagrammatic resummation at fixed renormalization scale?
I think the diagrams not only need to look like a series of loops, one encircling each others, but also need to be strongly ordered in loop momenta, with inner loops having much less momenta so appear as effective vertices to outer loops. In other words, we are looking at a reduced part of the phase space. The question is then how to prove it's this part of the phase space that gives leading behaviour. Another question is how to show that a generic N-loop diagram is "sub-leading" compared with diagrams that are reducible to N successive 1-loop diagrams.
Jan
14
asked How to prove equivalence of RG flow of QFT coupling constant and diagrammatic resummation at fixed renormalization scale?
Jan
6
asked Is the axial gauge with a $\xi$ term useful in Yang-Mills theory?
Dec
25
accepted Do people confuse all-order perturbation theory with non-perturbative physics in QFT?
Dec
17
comment Dimensional Regularization Integral Formula
I have an example where $\Delta$ is negative. Consider the one-loop EM vertex correction for fermion-fermion scattering in QED. Ignoring fermion masses, we have $\Delta=-x(1-x)q^2$, where $q^2$ is the photon virtuality. Now $q^2$ is -ve for t-channel elastic scattering, but +ve for s-channel scattering, so $\Delta$ may have either signs.
Dec
17
asked Dimensional Regularization Integral Formula
Dec
16
accepted Which collision energy at LHC is better for hunting 125 GeV Higgs, 7 TeV, 8 TeV or 14 TeV?
Dec
14
asked Which collision energy at LHC is better for hunting 125 GeV Higgs, 7 TeV, 8 TeV or 14 TeV?
Dec
5
comment Why GPS is at LEO?
Interesting. I knew that China's Beidou has a limited coverage region centered around China, but it's only after reading your comment that I finally understood why it has a well-defined coverage region at all.
Dec
2
asked Cusp anomalous dimension in QCD
Nov
28
answered Bloch oscillations - Scattering to other bands
Nov
28
comment What is the smallest distance between a decaying vertex and an interaction point a detector can measure?
@Revo: I guess the shortest distance should be comparable to the resolution quoted in the article. But if you are really asking for the shortest distance that can be distinguished from zero at a statistical significance, I don't know the answer.