Nonperturbative approach to finite-dimensional non-Gaussian integrals
Teoretičeskaâ i matematičeskaâ fizika, Tome 163 (2010) no. 3, pp. 495-504
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We study the homogeneous non-Gaussian integral $J_{n|r}(S)=\int e^{-S(x_1,\dots,x_n)}\,d^nx$, where $S(x_1,\dots,x_n)$ is a symmetric form of degree $r$ in $n$ variables. This integral is naturally invariant under $SL(n)$ transformations and therefore depends only on the invariants of the form. For example, in the case of quadratic forms, it is equal to the $(-1/2)$th power of the determinant of the form. For higher-degree forms, the integral can be calculated in some cases using the so-called Ward identities, which are second-order linear differential equations. We describe the method for calculating the integral and present detailed calculations in the case where $n=2$ and $r=5$. It is interesting that the answer is a hypergeometric function of the invariants of the form.
Keywords:
non-Gaussian integral, Ward identity, theory of invariants.
@article{TMF_2010_163_3_a12,
author = {Sh. R. Shakirov},
title = {Nonperturbative approach to finite-dimensional {non-Gaussian} integrals},
journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
pages = {495--504},
publisher = {mathdoc},
volume = {163},
number = {3},
year = {2010},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/TMF_2010_163_3_a12/}
}
Sh. R. Shakirov. Nonperturbative approach to finite-dimensional non-Gaussian integrals. Teoretičeskaâ i matematičeskaâ fizika, Tome 163 (2010) no. 3, pp. 495-504. http://geodesic.mathdoc.fr/item/TMF_2010_163_3_a12/