Decoupling-free NMR quantum computer on a quantum spin chain

摘要: We propose a decoupling-free nuclear-spin quantum computer installed on electron spin chain with singlet ground state and finite gap. Qubits are $I=1/2$ nuclear spins implanted periodically along the chain. A magnetic field gradient is applied parallel to chain, which allows individual access each qubit. single-qubit operation (rotation gate) realized rf tuned Larmor frequency at qubit of interest, while two-qubit (controlled-NOT achieved using Suhl-Nakamura interaction through packet triplet magnons, excited by microwave gap energy $(SN$ gate). The can be switched off turning microwave, realized. initialization an optical pumping initializer, has multilayered structure semiconductor. Spin polarizations created in semiconducting layers transferred cross polarization diffusion. scheme us separate process from computation, enabling optimize latter independently former.