Developing fast and accurate control and readout techniques is an importantchallenge in quantum information processing with semiconductor qubits. Here, westudy the dynamics and the coherence properties of a GaAs/AlGaAs double quantumdot (DQD) charge qubit strongly coupled to a high-impedance SQUID arrayresonator. We drive qubit transitions with synthesized microwave pulses andperform qubit readout through the state dependent frequency shift imparted bythe qubit on the dispersively coupled resonator. We perform Rabi oscillation,Ramsey fringe, energy relaxation and Hahn-echo measurements and findsignificantly reduced decoherence rates down to $gamma_2/2pisim 3,m{MHz}$corresponding to coherence times of up to $T_2 sim 50 , m{ns}$ for chargestates in gate defined quantum dot qubits.
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