Verification of a resetting protocol for an uncontrolled superconducting qubit

Quantum resetting protocols allow a quantum system to be sent to a state in the past by making it interact with quantum probes when neither the free evolution of the system nor the interaction is controlled. We experimentally verify the simplest non-trivial case of a quantum resetting protocol, known as the \(\mathcal{W}_4\) protocol, with five superconducting qubits, testing it with different types of free evolutions and target-probe interactions. After projection, we obtained a reset state fidelity as high as \(0.951\), and the process fidelity was found to be \(0.792\). We also implemented 100 randomly-chosen interactions and demonstrated an average success probability of \(0.323\) for \(|1\rangle\) and \(0.292\) for \(|-\rangle\), experimentally confirmed the nonzero probability of success for unknown interactions; the numerical simulated values are about \(0.3\). Our experiment shows that the simplest quantum resetting protocol can be implemented with current technologies, making such protocols a valuable tool in the eternal fight against unwanted evolution in quantum systems.