Introduce LER

src/thesis/chapters/2_fundamentals.tex

@@ -1660,6 +1660,12 @@ Algorithm \ref{alg:bpgd} shows this process.
 Note that as the Tanner graph only has $n$ \acp{vn}, this is a
 natural constraint on the maximum number of outer iterations of the algorithm.
 
+Quantum degeneracy additionally necessitates some care in the way
+error rates are computed in simulations.
+We must consider the fact that multiple solutions are valid by
+comparing the logical states, computed by measuring the logical operators.
+This way, we obtain the \ac{ler}.
+
 % TODO: Explain that setting the channel LLR to infinity is the same
 % as a hard decision and ignoring the VN in the further decoding
 % tex-fmt: off