High-fidelity CNOT gate for spin qubits with asymmetric driving using virtual gates

Recent experiments have demonstrated two-qubit gate fidelities above 99% for semiconductor spin qubits. However, theoretically, the fidelity of controlled-NOT (CNOT) operations is limited by off-resonant driving described by off-diagonal terms in the system Hamiltonian. Here, we investigate these off-diagonal contributions and we propose a fidelity improvement of several orders of magnitude by using asymmetric driving. Therefore, we provide a description of ac virtual gates based on a simple capacitance model which not only enables a high-fidelity CNOT but also allows for crosstalk reduction when scaling up spin qubit devices to larger arrays.