Spacetime Sentinels: a Qiskit game that exposes the competition between spacetime checks and magic in low-overhead quantum error detection

We present Spacetime Sentinels, a game in which the player protects a noisy circuit with spacetime Pauli checks and is scored on the post-selected fidelity and the fraction of shots that survive, with every number computed in Qiskit. The player spends a budget of ancilla qubits on checks found by th