Synchronization of multiple coupled rf-SQUID Flux Qubits

Another research paper that describes an aspect of how the Dwave System adiabatic quantum computer works.

Synchronization of multiple coupled rf-SQUID flux qubits (10 page pdf)

A practical strategy for synchronizing the properties of compound Josephson junction (CJJ) radio frequency monitored superconducting quantum interference device (rf-SQUID) qubits on a multi-qubit chip has been demonstrated. The impact of small (1%) fabrication variations in qubit inductance and critical current can be minimized by the application of a customtuned flux offset to the CJJ structure of each qubit. This strategy allows for a simultaneous synchronization of the qubit persistent current and tunnel splitting over a range of external bias parameters that is relevant for the implementation of an adiabatic quantum processor


A method for synchronizing the properties of multiple coupled CJJ rf-SQUID flux qubits with a small spread of device parameters due to fabrication variations was demonstrated. Both theory and experiment indicate that the application of a custom-tuned flux bias to each qubit CJJ loop is sufficient to compensate for ±1% differences in critical current. This strategy may prove to be an important step in the development of practical adiabatic quantum information processors.