Fidelity

Near-term quantum systems are noisy. Crosstalk noise has been recognized as one of the major types of noises in superconducting Noisy Intermediate-Scale Quantum (NISQ) devices. Crosstalk arises due to the interference of co-running gates, typically located in close physical proximity. Crosstalk can lead to a significant increase in the error rate of gates that are co-running, as compared to when they are operated independently. It can be mitigated through the scheduling of gates and/or pulses, which is a process that happens at later stages of compilation. However, in this paper, we discover that crosstalk mitigation can happen during the early stages of compilation, for instance, the circuit synthesis stage. We develop a cross-stack crosstalk mitigation framework named CQC. CQC demonstrated an average 29% fidelity improvement and 1.7X faster circuit execution compared to state-of-the-art when evaluated on real IBM_Q and Rigetti devices. In particular, real machine experiments on IBM Mumbai showed a 2.18X speed up and 82% fidelity improvement for VQE on the Li-H molecule compared to the prior approach.

The arXiv version of this crosstalk mitigation paper is here.