# Contents

## Idea

In quantum theory the state of a physical system is given by a vector in a complex vector space (usually a Hilbert space). This means that given any two states $\psi_1$ and $\psi_2$, also their sum as vectors $\psi_1 + \psi_2$ is represents a state. This is called the superposition of the two states.

Revised on January 23, 2014 06:24:28 by Urs Schreiber (82.113.121.190)