Quantum erasure channel
= Quantum erasure channel
{title2=$\mathcal E_p(\rho)=(1-p)\rho\oplus p|e\rangle\langle e|$}
A quantum erasure channel transmits an input state unchanged with probability $1-p$ and replaces it by an orthogonal, recognizable erasure flag with probability $p$. Its output space has one more dimension than the input. This is a <quantum channel> for $0\le p\le1$ and preserves all input coherences on the nonerased branch.