Evaluating a infinite-dimensional Gaussian integral

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SUMMARY

The discussion centers on evaluating the multi-dimensional Gaussian integral in the context of Quantum Field Theory (QFT). The integral presented is of the form ∫_{−∞}^{∞}d^{n}V exp(x^{T}Ax)exp(ag(g(x))) as n→∞. The challenge arises from the presence of the function g(x), complicating the evaluation. The user suggests the potential use of functional integration under an infinite-dimensional Gaussian Borel measure but seeks guidance on numerical methods applicable to infinite-dimensional spaces.

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Karlisbad
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Hello,.. that's part of a problem i find in QFT (i won't explain it since it can be very tedious), the question is that i must evaluate the Multi-dimensional Gaussian Integral.

\int_{-\infty}^{\infty}d^{n}V exp(x^{T}Ax)exp(ag(x))

for n\rightarrow \infty of course if the integral is "purely" a Gaussian then you can do it..:redface: :smile: however you have the problem of g(x), if you think you're integrating about 2paths" (trajectories), then my idea is that perhaps you could consider "functional integration" under a infinite dimensional Gaussian Borel Meassure, however i don't know more, i have the "(approximate) meassure but don't know any Numerical method valid for infinite dimensional spaces :confused: :confused: if a is small a Gaussian meassure could work but how do i perform the integral?.. thankx
 
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can you tell me something about this

\int dq_{1} dq_{2} (q_{1}^{2} + q_{1}q_{2}) exp[\mathbf{q}^{T}\mathbf{A}\mathbf{q}]

?
 

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