Scarlino, Pasqualevan Woerkom, D. J.Stockklauser, A.Koski, J. V.Collodo, M. C.Gasparinetti, S.Reichl, C.Wegscheider, W.Ihn, T.Ensslin, K.Wallraff, A.2021-03-262021-03-262021-03-262019-05-2210.1103/PhysRevLett.122.206802https://infoscience.epfl.ch/handle/20.500.14299/176131Developing fast and accurate control and readout techniques is an important challenge in quantum information processing with semiconductor qubits. Here, we study the dynamics and the coherence properties of a GaAs/AlGaAs double quantum dot charge qubit strongly coupled to a frequency-tunable high-impedance resonator. We drive qubit transitions with synthesized microwave pulses and perform qubit readout through the state-dependent frequency shift imparted by the qubit on the dispersively coupled resonator. We perform Rabi oscillation, Ramsey fringe, energy relaxation, and Hahn-echo measurements and find significantly reduced decoherence rates down to γ2/2π∼3 MHz corresponding to coherence times of up to T2∼50 ns for charge states in gate-defined quantum dot qubits. We realize Rabi π pulses of width down to σ∼0.25 ns.text::journal::journal article::research article