# Meaning of U

1. Oct 8, 2006

Meaning of "U"

If we have a One dimensional gas, so using $$\beta = \frac{1}{KT}$$

then we can define (if we knew partition function) the quantity U so:

$$U= - \frac{\partial LnZ}{\partial \beta}$$

which is called "inner energy" if we call the potential of the particles V(x) my question is if somehow U (inner energy) is the derivative of a potential or something similar

2. Oct 15, 2006

### masudr

U is the internal energy of the system. Why would it be the derivative of a potential (which, by the way, is usually a force or force field)?