# state-operator correspondence

The state-operator correspondence is a correspondence between states $\left|\Phi\right\rangle\,$ and Heisenberg picture operators $\Phi\,$, given by
$\Phi \leftrightarrow \left| \Phi \right\rangle = \lim_{t\to-\infty} \Phi(t) \left| 0\right\rangle\,$.