Content deleted Content added
m →Gaussian integrals: typo + post merge cleanup (Grassmann integral to Berezin integral) |
|||
Line 88:
==Expectation values==
The partition function is commonly used as a [[probability-generating function]] for [[expectation value]]s of various functions of the random variables. So, for example, taking <math>\beta</math> as an adjustable parameter, then the derivative of <math>\log(Z(\beta))</math> with respect to <math>\beta</math>
:<math>\mathbf{E}[H] = \langle H \rangle = -\frac {\partial \log(Z(\beta))} {\partial \beta}</math>
| |||