Bad Qubits — Learn Quantum by Doing

Multiple choice

For this circuit, what is the probability that measuring all 3 qubits yields exactly |100⟩ (qubit 0 leftmost)?

⚛ The apparatus

const c = circuit(3);
// Periodic superposition: (|000>+|010>+|100>+|110>)/2
c.h(0);
c.h(1);
// Inverse QFT (adjoint of QFT including bit-reversal swap)
c.swap(0, 2);
c.h(2);
c.cp(-Math.PI / 2, 2, 1);
c.h(1);
c.cp(-Math.PI / 4, 2, 0);
c.cp(-Math.PI / 2, 1, 0);
c.h(0);
return c;

Commit your prediction for P(|100⟩) — then run it.