We show strong positive spatial correlations in the qubits of a D-Wave 2000Q quantum annealing chip that are connected to qubits outside their own unit cell. By simulating the dynamics of spin networks, we then show that correlation between nodes is affected by a number of factors. The different connectivity of qubits within the network means that information transfer is not straightforward even when all the qubit-qubit couplings have equal weighting. The similarity between connected nodes is further changed when the couplings’ strength is scaled according to the physical length of the connections (here to simulate dipole-dipole interactions). This highlights the importance of understanding the architectural features and potentially unprogrammed interactions/connections that can divert the performance of a quantum system away from the idealised model of identical qubits and couplings across the chip.
@inproceedings(Park++:2023-UCNC, author = "Jessica Park and Susan Stepney and Irene d'Amico", title = "Spatial correlations in the qubit properties of D-Wave 2000Q measured and simulated qubit networks", pages = "140-154", doi = "10.1007/978-3-031-34034-5_10", crossref = "UCNC-2023" ) @proceedings(UCNC-2023, title = "UCNC 2023, Jacksonville, Florida, USA, March 2023", booktitle = "UCNC 2023, Jacksonville, Florida, USA, March 2023", series = "LNCS", volume = 14003, publisher = "Springer", year = 2023 )