Noise-Aware Error Rate Reduction of Single-Qubit Gates

In the current era of Noisy Intermediate-Scale Quantum technology, the practical use of quantum computers remains inhibited by computational errors arising from our inability to aptly decouple qubits from their environment. In this work, we introduce a protocol by which knowledge of the initial quantum state (e.g., after qubit initialization) and standard parameters describing the system’s noise can be leveraged to reduce the noise present during the execution of a single-qubit gate. We benchmark our protocol using cloud-based access to 2 of IBM’s 5-qubit devices. On one, we demonstrate a reduction in single-qubit error rates by 38%, from 1.6e-3 to 1.0e-3, provided the initial quantum state is known. On the other, we demonstrate the protocol’s resilience to drifts and miscalibrations in coherence times by using T1 and T2 times offset from their true values by up to 2 orders of magnitude to nonetheless outperform default hardware gate implementations. The protocol can be used to improve the fidelity of both quantum state preparation and quantum circuits for which some knowledge of the qubits’ intermediate states can be inferred. This work presents a pathway to using information about noise levels to significantly reduce the error rates associated with single- and two-qubit gates.