3-Qubit Syndrome Tester: Manual Bit-Flip Injection

Real quantum hardware is never tested by directly reading out a qubit mid-computation — that measurement would destroy the very superposition being protected. Instead, engineers test and verify quantum memories with syndrome measurement: ancilla parity checks that reveal where an error happened without revealing (or collapsing) what the logical state actually is. This simulator lets you inject bit-flip errors on any of three physical qubits by hand, run the two real stabilizer measurements Z₁Z₂ and Z₂Z₃, and watch the standard majority-vote decoder recover the logical state. Flip one qubit and correction always succeeds. Flip two, and you can watch the code fail exactly the way it does on real hardware — a genuine limitation shown honestly, not hidden.