Superconducting qubits
Transmon chips designed, fabricated and measured in house.
The question
Why does a qubit forget — and which part of the chip is to blame?
We track coherence for weeks at a time, map the tiny defects (two-level systems) that steal energy from a qubit, and redesign couplers and wiring so that flux noise and heat stay out of the chip.
Methods, tools and data
| Devices | Fixed-frequency and flux-tunable transmons, tunable couplers |
|---|---|
| Fabrication | Aluminium and tantalum films, Josephson junctions by double-angle evaporation |
| Measurements | T1/T2 tracking over weeks, two-level-system spectroscopy, gate calibration |
| Data | Coherence logs shared with collaborators on request |
Representative papers
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25
“Leakage-aware decoding for heavy-square surface codes on fixed-frequency transmons”
Quantum Device Letters, Vol. 14, 092301, 2026
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24
“Two-level-system spectroscopy of tantalum transmons with a tunable flux probe”
Journal of Applied Quantum Engineering, Vol. 8, No. 4, pp. 211–224, 2026
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18
“Pulse-level calibration of cross-resonance gates with Bayesian experiment design”
Quantum Device Letters, Vol. 13, 081104, 2025
People on this topic
- Dohyun HanPostdoctoral Researcher · Tunable couplers and flux-noise filtering
- Hyunwoo ChoPh.D. Student · Two-level-system defects in transmons
- Haram KimM.S. Student · Long-term coherence tracking
- Gunwoo JangM.S. Student · Cryogenic microwave wiring
- Gyeol PyoUndergraduate Researcher · Fridge monitoring dashboard