Entanglement swapping
= Entanglement swapping
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Two initial maximally entangled pairs $AB_1$ and $B_2C$ can be turned into an entangled pair $AC$ by a <generalized Bell basis> measurement on $B_1B_2$, followed by a local correction at an endpoint using its classical label. This is <qudit teleportation> of $B_1$, including its correlations with $A$, to $C$. The initial two pairs are consumed. Without the classical label, averaging the conditional endpoint states need not leave entanglement.