Spin qubits in GaAs quantum dots – progress towards scalability

The performance of qubits consisting of electron spins in semiconductors trapped via electrostatic gates has seen dramatic improvements over the last few years. In particular, the measured dephasing times associated with electrical noise and nuclear spin fluctuations were increased by orders of magnitude, and high fidelity single shot readout has been realized. To make further progress, it is essential to realize high fidelity gates for single and multiple qubits. One milestone is our recent demonstration and characterization of a two-qubit entangling gate.For single qubit gates, we find from a numerical optimization based on the measured dephasing times and taking realistic constraints into account that fidelities approaching the threshold required for quantum error correction should be achievable. I will conclude with an outlook of what is needed beyond these promising results to move further along the path towards scalable semiconductor qubits that are viable for quantum information processing.