GRW localization operator
= GRW localization operator
{c}
{title2=$L_i(\mathbf X)$}
For localization <length> $r_C$, the <GRW localization operator> acting on particle $i$ is
$$
L_i(\mathbf X)=(\pi r_C^2)^{-3/4}
\exp\left[-\frac{(\mathbf q_i-\mathbf X)^2}{2r_C^2}\right].
$$
A collapse centred at $\mathbf X$ sends $|\psi\rangle$ to the normalized state $L_i(\mathbf X)|\psi\rangle$ with <probability> density $\|L_i(\mathbf X)|\psi\rangle\|^2$.