Periodic Reporting for period 1 - IGNITE (Integrated GermaNIum quanTum tEchnology)
Reporting period: 2022-07-01 to 2023-12-31
Spin qubits in germanium have resulted in the most advanced semiconductor quantum processor. Within five years of development, germanium qubits are established as a highly promising candidate for large-scale quantum computing.
Germanium is a standard semiconductor manufacturing material and germanium qubits are the only semiconductor qubits that are defined exclusively by transistor-based structures and has enabled to demonstrate a universal quantum gate set [Hen20]. This is highly promising for scalability and adoption by leading semiconductor technology. A revolution in the growth of strained germanium sparked a remarkable development which led to the first germanium quantum dot, germanium qubit, two-qubit logic in germanium, four-qubit logic in a two-dimensional array, and operation of a 16 quantum dot array. This program brings together all the partners that enabled these developments to form a consortium with leading scientists and industry, to fulfil the promise of germanium quantum technology, by scaling the number of qubits, by designing architectures allowing to advance beyond 1000s of qubits, and by experimentally implementing a computational task that can provide a quantum advantage. The key objective of Integrated Germanium Quantum Technology (IGNITE) is thus to demonstrate that germanium defines a compelling platform for quantum computation with excellent qubits operating in a scalable network. We therefore focus on four key components to demonstrate its success.
Germanium is a standard semiconductor manufacturing material and germanium qubits are the only semiconductor qubits that are defined exclusively by transistor-based structures and has enabled to demonstrate a universal quantum gate set [Hen20]. This is highly promising for scalability and adoption by leading semiconductor technology. A revolution in the growth of strained germanium sparked a remarkable development which led to the first germanium quantum dot, germanium qubit, two-qubit logic in germanium, four-qubit logic in a two-dimensional array, and operation of a 16 quantum dot array. This program brings together all the partners that enabled these developments to form a consortium with leading scientists and industry, to fulfil the promise of germanium quantum technology, by scaling the number of qubits, by designing architectures allowing to advance beyond 1000s of qubits, and by experimentally implementing a computational task that can provide a quantum advantage. The key objective of Integrated Germanium Quantum Technology (IGNITE) is thus to demonstrate that germanium defines a compelling platform for quantum computation with excellent qubits operating in a scalable network. We therefore focus on four key components to demonstrate its success.
Main achievements
WP2:
- Successful delivery of purified germanium to TU Delft and IMEC.
- Growth of strained Ge/SiGe heterostructures on Ge wafers, resulting in significant reduction in threading dislocation density and enhanced properties for next-generation Ge spin-qubits.
WP3:
- Development of depletion mode spin qubits in planar Ge with quality factors exceeding 500.
- Detailed fabrication processes described, including operation at low magnetic fields and measurement of qubit coherence.
- Novel techniques for calibrating and adjusting qubit parameters to enhance quality factors.
- Ongoing exploration of Ge singlet-triplet qubits and optimization of single-qubit performance.
- High quality single-qubit and two-qubit gates and operation of extended quantum dot arrays.
WP4:
- Development of QDsim simulation package for generating charge stability diagrams of quantum dot systems.
- Achievement of faster convergence in charge stability diagram calculation through convex optimization.
- Active involvement in automated tuning of quantum dot devices, including expansion to Germanium devices as Ge singlet-triplet qubits.
WP2:
- Successful delivery of purified germanium to TU Delft and IMEC.
- Growth of strained Ge/SiGe heterostructures on Ge wafers, resulting in significant reduction in threading dislocation density and enhanced properties for next-generation Ge spin-qubits.
WP3:
- Development of depletion mode spin qubits in planar Ge with quality factors exceeding 500.
- Detailed fabrication processes described, including operation at low magnetic fields and measurement of qubit coherence.
- Novel techniques for calibrating and adjusting qubit parameters to enhance quality factors.
- Ongoing exploration of Ge singlet-triplet qubits and optimization of single-qubit performance.
- High quality single-qubit and two-qubit gates and operation of extended quantum dot arrays.
WP4:
- Development of QDsim simulation package for generating charge stability diagrams of quantum dot systems.
- Achievement of faster convergence in charge stability diagram calculation through convex optimization.
- Active involvement in automated tuning of quantum dot devices, including expansion to Germanium devices as Ge singlet-triplet qubits.
We demonstrated a new technique for qubit operation based on discrete pulses. This allowed us to operate with low power control and obtain single qubit gates fidelities above 99.9%, displacement fidelities above 99.99% and a two-qubit gate fidelity of 99.3%. Additionally, we have developed superior germanium quantum wells by utilizing germanium wafers. These results mark an important step in establishing germanium as a compelling platform for quantum computation.