QDev Seminar: Andrew Doherty – University of Copenhagen

QDev Seminar: Andrew Doherty

Exchange-coupled semiconductor qubits

Exchange coupling of semiconductor qubits is a potential means of performing universal quantum computation in near future experiments. In typical settings, such as coupling singlet-triplet or exchange-only qubits, exchange coupling does not work straightforwardly because of leakage due to spin-flip transitions. Recently we have demonstrated that these spin-flip transitions can be made energy-nonconserving by magnetic field gradients in the case of singlet-triplet qubits, and by suitable intra-qubit exchange coupling in the case of exchange-only qubits. When combined with smooth adiabatic inter-qubit exchange pulses this leads to very simple two-qubit gate implementations in either case. In this talk I will describe our recent investigations of the affect of charge noise and nuclear fields on these qubit implementations.