Jonginn Yun

Hamiltonian-estimation, coherent-control, and interaction-characterization workflows for semiconductor spin-qubit experiments.

This project summarizes coherent-control, readout, and interaction-characterization work in semiconductor spin-qubit platforms, including GaAs and isotopically enriched silicon/silicon-germanium quantum-dot systems. The experimental workflow includes cryogenic device operation, automated measurements, pulse calibration, Hamiltonian estimation, randomized benchmarking, and gate-set tomography.

In GaAs quantum-dot arrays, I played a central role in Hamiltonian-estimation and readout-optimization workflows. The experiments combined energy-selective tunneling readout, Bayesian parameter estimation, and active control to stabilize qubit frequencies, reduce drift, and improve high-visibility qubit operation.

For two-qubit operation, I co-led the experimental workflow for characterizing capacitive coupling between singlet-triplet qubits beyond the bilinear regime. I executed key experiments, implemented the dual Hamiltonian parameter-estimation workflow, and performed primary analysis for two-qubit coupling characterization.

In Si/SiGe devices, the work studied singlet-triplet qubit coherence and coupling to nearby many-electron spin states. These measurements connect qubit control, charge configuration, and environmental degrees of freedom in a platform relevant to scalable semiconductor quantum processors.