Error Mitigation by Restricted Evolution

Error mitigation techniques, while instrumental in extending the capabilities of near-term quantum computers, often suffer from exponential resource scaling with noise levels. To address this limitation, we introduce a novel approach, constant runtime Error Mitigation by Restricted Evolution (EMRE). Through numerical simulations, we demonstrate that EMRE surpasses the performance of Probabilistic Error Cancellation (PEC) while maintaining constant sample complexity. Moreover, we uncover a continuous family of error mitigation protocols, Hybrid EMREs (HEMREs), encompassing PEC and EMRE as special cases. HEMREs offer a tunable bias parameter, allowing for a trade-off between sample complexity and error reduction. Thus, our error mitigation protocols provide flexibility in balancing error mitigation with computational overhead, catering to practical application requirements of near-term and early-fault tolerant quantum devices.