Last time I set the stage, the mathematical location for quantum mechanics, a complex vector space (Hilbert space) where the vectors represent quantum states. (A wave-function defines where the vector is in the space, but that’s a future topic.)

The next mile marker in the journey is the idea of a ** transformation** of that space using

**. The topic is big enough to take two posts to cover in reasonable detail.**

*operators*This first post introduces the idea of (*linear*) ** transformations**.