Finite-round quantum error correction on symmetric quantum sensors (2212.06285v4)

Abstract: The Heisenberg limit provides a quadratic improvement over the standard quantum limit, and is the maximum quantum advantage that quantum sensors could provide over classical methods. This limit remains elusive, however, because of the inevitable presence of noise decohering quantum sensors. Namely, if infinite rounds of quantum error correction corrects any part of a quantum sensor's signal, a no-go result purports that the standard quantum limit scaling can not be exceeded. We side-step this no-go result by using an optimal finite number of rounds of quantum error correction and an adaptive procedure of signal recovery, such that even if part of the signal is corrected away, our quantum field sensing protocol's precision can approach the Heisenberg limit despite a linear rate of deletion errors. Our protocol is based on quantum error correction codes within the symmetric subspace, which admit near-term implementations using quantum control techniques.