Coherent manipulation of the Si/SiGe quantum dot hybrid qubit using single-shot latched readout

We present single-shot measurements and demonstrate coherent Larmor oscillations of a quantum dot hybrid qubit. Single-shot readout is performed through a single reservoir coupled to a 5-electron double dot in the (4,1)-(3,2) charge configuration. Latching onto the (4,2) charge state is achieved by simultaneously pulsing the gate voltages on barrier and plunger gates, thereby enabling dynamic control of the tunnel rates. We further show that similar pulses on the same gates can speed up qubit initialization by a factor of 15, greatly increasing experimental throughput. We demonstrate that crosstalk between the barrier gates and the quantum dots is only significant for adjacent dots, so that a simple correction scheme is sufficient to fully cancel out the crosstalk. Finally, we discuss the application of our latching scheme to any qubit whose spin states can be adiabatically transformed to charge states of a double quantum dot, including singlet-triplet qubits, exchange-only qubits, and single-spin qubits in parity readout mode.