Position Operator in Quantum Mechanics
Definition
In quantum mechanics, the position operator $X$ is defined as follows for a wave function $\psi(x, t)$:
$$ X \psi(x, t) = x \psi(x, t) $$
Description
The equation where the position operator is applied to a wave function can be interpreted in quantum mechanics as the act of measuring (observing) the position of the wave function.