Scaling up spin qubit systems requires high-fidelity single-qubit and two-qubit gates. Gate fidelities exceeding 99% were already demonstrated in silicon based quantum dots, whereas for the realization of larger qubit arrays crosstalk effects on neighboring qubits must be taken into account. We analyze qubit and gate fidelities impacted by driving fields when performing single-qubit and two-qubit operations with a simple Heisenberg model. Furthermore we propose conditions for driving fields to robustly optimize qubit gates and avoid crosstalk effects leading to a restricted choice for the driving field strength, exchange interaction, and thus gate time. Considering realistic experimental conditions we propose a set of parameter values to perform an optimal CNOT gate and provide a description of an ac virtual gate based on a simple capacitance model which not only enables a high fidelity CNOT but also crosstalk reduction when scaling up spin qubit devices and so open up the pathway to scalable quantum computing devices.
University of Konstanz
Title of Poster
Optimizing single-qubit and two-qubit gates in spin qubit arrays