A realistic GaAs-spin qubit device for a classical error-corrected quantum memory and beyond

Based on numerically-optimized real-device gates and parameters we study the performance of the phase-flip (repetition) code on a linear array of GaAs quantum dots hosting singlet-triplet qubits. We first examine the expected performance of the code using simple error models of circuit-level and phenomenological noise, reporting a.o. a 3% circuit-level depolarizing noise threshold. We then perform density-matrix simulations using a maximum-likelihood and minimum-weight matching decoder to study the effect of real-device dephasing, read-out error, quasi-static as well as fast gate noise. Considering the trade-off between qubit read-out time versus dephasing time (T2), we identify a sub-threshold region for the phase-flip code which lies within experimental reach.