Low-Error Operation of Spin Qubits with Superexchange Coupling

Abstract: In this theoretical work we investigate superexchange, as a means of indirect exchange interaction between two single electron spin qubits, each embedded in a single semiconductor quantum dot (QD). The exchange interaction is mediated by an intermediate, empty QD. Our findings suggest the existence of first order "super sweet spots", in which the qubit operations implemented by superexchange interaction are simultaneously insensitive to charge noise and errors due to spin-orbit interaction. We also find that the sign of the superexchange can be changed by varying the energy detunings between the QDs.