ISOCTA
Institute for Scientific Operations, Cryogenics & Technical Applications

Quantum Information Division

Figure 1: Dilution refrigerator in Building 2 configured for qubit measurement. The shielded insert (centre) contains a superconducting flux qubit chip with on-chip SQUID readout. The coaxial and DC wiring looms enter from the top of the cryostat through microwave-grade hermetic feedthroughs.

The Quantum Information Division, led by Dr. Samuel Park, is ISOCTA's smallest research division, comprising four scientists and one technician. The programme focuses on solid-state qubit architectures and the cryogenic measurement infrastructure required to coherently manipulate and read out quantum systems at millikelvin temperatures.

Research Programmes

Solid-State Qubit Architectures

Fabrication and measurement of superconducting flux and phase qubits using Nb/Al-AlOx/Nb trilayer Josephson junction technology. Current work targets improved coherence times through materials optimisation and electromagnetic environment engineering. Measurement is performed in dilution refrigerators at base temperatures below 20 mK. » Programme page

High-Q Cryogenic Sapphire Resonators

Development of cryogenic sapphire dielectric resonators exhibiting quality factors exceeding 109 at microwave frequencies, for use as frequency references and quantum-limited measurement circuits. Operated at liquid helium temperatures in collaboration with the Cryogenics group (Building 2). » Programme page

SQUID Magnetometry

DC and RF SQUID development for quantum state readout and for high-sensitivity magnetic measurements in support of other Institute programmes, including the Magnetic Materials group and the Biotechnology Division. » Programme page

Quantum Optics

Small-scale programme in collaboration with the Photonics Division investigating entangled photon-pair sources based on spontaneous parametric down-conversion in periodically-poled crystals. » Programme page

Facilities & Equipment

SystemSpecification
Dilution refrigerator (primary)Wet dilution unit, base <14 mK, 40 μW @ 100 mK, 24 DC + 8 RF lines
Dilution refrigerator (secondary)Wet unit, base <30 mK, 16 DC + 4 RF lines, rotatable sample stage
Helium liquefier35 L/hr, 500 L storage dewar, recovery system for boil-off
Josephson junction fabricationShared use of Building 1 cleanroom: e-beam lithography, double-angle evaporation
Low-noise measurementDC SQUID amplifiers, HEMT cryogenic preamplifiers, vector network analyser to 20 GHz

Key Personnel

  • Dr. Samuel Park — Division Head. Superconducting qubits, quantum measurement.
  • Dr. Robert Chen — Joint appointment (Electromagnetic Systems). SQUID development.
  • Additional research staff: 2 scientists, 1 technician.

Note on Programme Scope

The Quantum Information programme is limited in scale and does not pursue fault-tolerant quantum computing or large-scale qubit integration. Current work is focused on single- and few-qubit physics, measurement techniques, and enabling cryogenic infrastructure.

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