Using Grover's search algorithm to test state-of-the-art quantum platforms*

In the present work, Grover's search algorithm is used to study performance of state-of-the-art quantum platforms, such as LLNL Quantum Design and Integration Testbed (QuDIT), Rigetti and IBM-Q. The algorithm is suited for three and four level quantum systems, thus, it is implemented on 2 qubits on Rigetti and IBM platforms and on a single transmon on the LLNL QuDIT. The population of the desired state is measured for different number of Grover's iterations and the results are compared to the analytically derived solution. The performance of the algorithm depends on the number of the system states, the marked state of the Oracle and the number of iterations. The observed fidelity loss is noticeably less for the LLNL QuDIT, as a small number of specially designed control pulses is used instead of a large sequence of native gates. For better understanding of the nature of the coherent and decoherent processes causing the fidelity decay, the algorithm is decomposed to main blocks and all of them are tested individually.