Multiple choice
For this circuit, what is the probability that measuring all 3 qubits yields exactly |101⟩ (qubit 0 leftmost)?
// Step 1: put qubit 0 into an equal superposition. const c = circuit(3); c.h(0); // After h(0): (1/sqrt(2))(|000> + |100>) // Step 2: flip q1 when q0=0 (zero-controlled CNOT on q1). // Wrap CX(0->1) between two X(0) gates. c.x(0); c.cx(0, 1); c.x(0); // After this block: (1/sqrt(2))(|010> + |100>) // Step 3: flip q2 when q0=1 (standard CNOT). c.cx(0, 2); // After cx(0,2): (1/sqrt(2))(|010> + |101>) return c;
Commit your prediction for P(|101⟩) — then run it.