Tagged Questions
4
votes
0answers
94 views
Confused by renormalization [duplicate]
Possible Duplicate:
Suggested reading for renormalization (not only in QFT)
I'm trying to learn QFT. I don't quite understand why renormalization works. If you are calculating a Feynman ...
2
votes
2answers
148 views
Gaussian type integral with negative power of variable in integrand
How can we compute the integral $\int_{-\infty}^\infty t^n e^{-t^2/2} dt$ when $n=-1$ or $-2$? It is a problem (1.11) in Prof James Nearing's course Mathematical Tools for Physics. Can a situation ...
6
votes
2answers
147 views
Is the step of analytic continuation unavoidable or can you model around it?
One sometimes considers the analytic continuation of certain quantities in physics and take them seriously. More so than the direct or actual values actually. For example if you use the procedure for ...
2
votes
0answers
112 views
Functional determinant approximation
Let the Hamiltonian in one dimension be $H+z$, then I would like to evaluate $\det(H+z)$.
I have thought that if I know the function $Z(t) = \sum_{n>0}\exp(-tE_{n})$ I can use
$$\sum_{n} ...
3
votes
2answers
213 views
How are functional determinants of Laplace-type operators used in physics?
Many mathematical papers concerning the $\zeta$-regularized Determinant of Laplace-type operators refer for motivation to the broad use of such determinants in mathematical physics, especially in ...
6
votes
4answers
561 views
Is QFT mathematically self-consistent?
After recently going through a short program of self-study in quantum mechanics, I was surprised to find a quote attributed to Feynman essentially saying he was extremely bothered by the computational ...
13
votes
5answers
130 views
Other processes than formal power series expansions in quantum field theory calculations
I am not sure if this question is too naive for this site, but here it goes. In QFT calculations, it seems that everything is rooted in formal power series expansions, i.e. , what dynamical systems ...
3
votes
2answers
264 views
Pade Approximant
I have some questions about Pade approximants.
Given a divergent power series $ \sum_{n >0} a(n)x^{n} $ can we use a Pade Approximant to it $ R(x)$ so we can obtain a SUM of the series for every ...
9
votes
2answers
571 views
Are there books on Regularization and Renormalization in QFT at an Introductory level?
Are there books on Regularization and Renormalization, in the context of quantum field theory at an Introductory level? Could you suggest one?
Added: I posted at math.SE the question Reference ...
8
votes
1answer
462 views
Iterated dimensional regularization
Given a 2-loop divergent integral $\int F(q,p)\,\mathrm{d}p\mathrm{d}q$, can it be solved iteratively? I mean
I integrate over $p$ keeping $q$ constant
Then I integrate over $q$
In both iterated ...
5
votes
2answers
1k views
Limit of Lorentzian is Dirac Delta
I have a quick question that just came up in my research and I could not find an answer anywhere so I thought I'd try here.
So one of the definitions of the Dirac Delta is the limit of the Lorentzian ...
5
votes
6answers
761 views
Laplacian of $1/r^2$ (context: electromagnetism and poisson equation)
We know that a point charge $q$ located at the origin $r=0$ produces a potential $\sim \frac{q}{r}$, and this is consistent with the fact that the Laplacian of $\frac{q}{r}$ is
...
13
votes
3answers
509 views
Does renormalization make quantum fields into (slightly) nonlinear functionals of test functions?
Quantum fields are presented as operator-valued distributions, so that the operators in the theory are linear functionals of some test function space. This works well for free fields, giving us a ...
21
votes
13answers
2k views
Suggested reading for renormalization (not only in QFT)
What papers/books/reviews can you suggest to learn what renormalization "really" is? Standard QFT textbooks are usually computation-heavy and provide little physical insight in this respect - after my ...
