I encountered notions of block length and error rate for quantum error correcting codes, which literature seems to just assume. Can someone please give precise definitions for these?
Usually we denote a quantum code by parameters $[[n,k,d]]$. Where $n$ is the number of physcial qubits used, $k$ - number of encoded (or logical) qubits, and $d$ the code distance.
Besides the definitions, how are block length and error rate related to those parameters $n,k$ and $d$?