Squeezed one-photon state
= Squeezed one-photon state
{title2=$S(r)|1\rangle$}
<photon addition> to an <optical squeezed vacuum> gives $a^\dagger S|0\rangle=\cosh r\,S|1\rangle$; subtraction gives $aS|0\rangle=-\sinh r\,S|1\rangle$. After successful-event normalization these are the same state up to phase, with mean occupation $1+3\sinh^2r$ and odd <photon> parity. At zero squeezing subtraction never succeeds; the normalized limiting state is not an output at that exact parameter value.