Master Defense

Amber Heskes

Pulsed gate experiments in two-dimensional semiconductor quantum dot arrays

Spin qubits hosted in industry-fabricated silicon quantum dot devices have good prospects of tackling the scalability challenge that comes with realizing a large-scale, fault-tolerant quantum information processor. High-fidelity single- and two-qubit gates as well as long coherence times have been successfully demonstrated using spin qubits hosted in silicon QD devices.  A challenge in the operation of spin qubits hosted by (industry-fabricated) Si  QD-devices is the complex valley-orbital structure that is unknown a priori and highly dependent on the atomic details of the confining interface, thereby strongly deviating from device to device.

 Here, we probe the DQD two-electron spectrum in a foundry-fabricated silicon-on-insulator device by performing pulsed gate experiments. We report the observation of enhanced relaxation rates at distinguishable values of the double dot detuning. The measurements are based on time-resolved measurements using gate-based dispersive RF sensing while applying a self-compensating detuning-axis pulse cycle. 

 In addition, a singlet-triplet qubit is realized in a GaAs/AlGaAs heterostructure device to be exploited as a machine learning test qubit in future experiments.

MS Teams link:  Master Thesis Presentation - Amber Heskes