# Time dependent quantum generators for the Galilei group

### What is it about?

Ray representations are consequence of Wigner's theorem. So, if, following Bargmann, we calculate the ray representation of Galilei's group, we can observe the connection between the characteristics of the representation and the physical system described by the group. With some simple calculation, using the work of Doebner-Mann, we can find the time dependent ray representation of Galilei's group for (2+1) and (3+1)-dimensions.

### Why is it important?

First of all it complete the representations of the Galilei's group. After could be the way to introduce the photon localizzability.

The following have contributed to this page: Gianluigi Filippelli