# Mathematical Physics. Path integrals

1. Apr 8, 2007

### samirdz

Hello all
I need some special help concerning the path integrals and exactely about the techniques of Fradkin-Gitman and also the technique of Alexandrou et al., what's they're exactely about ?. (what does it mean here al. in "Alexandrou et al." )
Thank you very much for every valuable help of any kind
Bye

2. Apr 8, 2007

### StatMechGuy

First off, I'm gathering you're reading papers, so giving the full citation would be helpful. Where did you get these, and what are they doing?

To answer your easier question, "et al." is short for "et alia" which is Latin for "and others". So there's probably four or five authors on the paper and they didn't want to write them all out.

3. Apr 10, 2007

### tpm

Has anyone read at 'Arxiv.org' the paper by "De-Witt Morette" recalling functional integration ?? i don't know if they at last introduce an acdequate measure for path integrals..also i have asked myself if there would be a possible method to evaluate them by infinite-dimensional MOntecarlo's method (without discretizying space-time) or using an analogue of Gaus quadrature formula with the infinite-dimensional analogue of Legendre Polynomials.

The idea si quite easy..Gaussian method used to evaluate:

$$\int_{-1}^{1} dx f(x) = \sum_{i} C_{i} f(x_i )$$

then we used "Gaussian quadrature" to evaluate the function at a certain chosen point so the error was the least possible.

When dealing with Path integrals this all becomes:

$$\int \mathcal D [f] F[f] =\sum_{i} C_{i} F[f_{i} (x)]$$

in this case you use a certain functions f1, f2, f3 ,f4,..... to evaluate the path integral, the main problem is what functions (in general) do you choose so the error in the functional integral above is minimum ??

Last edited: Apr 10, 2007
4. Apr 10, 2007

### samirdz

gaussian functional integrals, Grassmannian

Hello
I need the formula for calculating the gaussian functional integrals with the grassmannian variables (gaussian with quadratic plus linear term).

Also, how to enter new styles in the scientific workplace ..