NCCR SPIN

The Department of Physics heads National Centre of Competence in Research (NCCR) for the development of a silicon-based quantum computer.

Researchers around the world are searching for suitable ways to develop a quantum computer. There are currently a number of approaches to creating the building blocks from which the supercomputers of the future might be made. However, no matter what the approach, developing a quantum computer that is capable of tackling unresolved, important real-world problems presents an immense challenge. The main problem lies in the limited scalability of the existing systems.

That is where the NCCR SPIN: Spin Qubits in Silicon comes in. The goal is to develop an exceptionally scalable technology to enable the construction of a universally usable quantum computer. Professor Dominik Zumbühl and his team are pinning their hopes on silicon, a semiconductor that has been a proven material in the industry for decades. They are convinced that silicon technology is highly promising in enabling the on-chip integration of billions of components, leading to a particularly high-performance quantum computer.

The researchers in the «SPIN» team have been successfully working on spin qubits in quantum computing for many years, though their work has focused primarily on other types of semiconductors. Producing silicon nanostructures for qubits is especially difficult and is therefore being carried out in collaboration with the IBM research laboratory in Rüschlikon. This industrial research lab has the necessary expertise in silicon nano fabrication and will, among other things, take on manufacturing the prototypes using silicon components.

Aims

Initially, the main objective of the NCCR «SPIN» will be to develop reliable, fast, compact and scalable spin qubits in silicon. In the medium term, the results should make it possible to use spin qubits to perform calculations that would be impossible without a quantum computer. The long-term goal to which the NCCR «SPIN» wants to make a fundamental contribution is the creation of a universally usable quantum computer with more than a thousand logical qubits that are each based on a large number of spin qubits and work with no errors due to «quantum error correction».

The funding of an NCCR is spread over three funding phases, each lasting four years. The Swiss National Science Foundation (SNSF) is supporting the NCCR with CHF 17 million in the first funding phase from 2020 to 2023 and with 20.4 million Swiss francs in the second phase from 2024 to 2028.

This is a silicon plate, a so-called wafer. Modern computer chips, such as those we know from our smartphones or tablet PCs, have billions of transistors. Although a single transistor can only be a few nanometers in size, industrially manufactured silicon wafers can have a circumference of up to 30 cm. The semiconductor silicon has properties that make it very attractive for applications in the field of quantum technology. As part of their SPIN project, Prof. Warburton and his team are planning to use classical silicon semiconductor technology to build a spin quantum computer. Photo: IBM Research-Zurich.link.zoom
To implement their ambitious goals, the Basel researchers are supported by IBM Research-Zurich as an industrial partner. IBM has decades of expertise in the field of industrial semiconductor manufacturing. The first prototypes of the spin quantum processors are to be produced in the ultra-modern IBM clean room facilities in Rüschlikon. Image: IBM Research-Zurich.link.zoom
In order to operate a silicon transistor as a spin qubit, it is cooled in special refrigerators to temperatures close to absolute zero. Image: © Christian Flierl, University of Basel.link.zoom
In very close analogy to the functionality of a classical silicon transistor, spin qubits are also controlled or read out from the outside by applying both low and high frequency electrical signals. Image: © Christian Flierl, University of Basel.link.zoom
The experiments carried out by Prof. Warburton and his team are very complex, but at the same time very promising and so advanced that the construction of a functioning spin quantum computer appears to be an ambitious but realistic goal. Image: © Christian Flierl, University of Basel.link.zoom
Prof. Daniel Loss and Prof. Jelena Klinovaja are experts in the field of theoretical implementation of a spin-based quantum computer. With his groundbreaking scientific work, Prof. Loss already brought the idea of the spin qubit to life 20 years ago. Image: © Christian Flierl, University of Basel.link.zoom
Overview of the participating universities and the industrial partner. Map: hubbuchmedia.chlink.zoom

Interdisciplinary network

The NCCR «SPIN» is led by Professor Dominik Zumbühl with the support of Professor Daniel Loss (Co-Director), Dr. Heike Riel from IBM Research – Zurich (Deputy Director) and Professor Jelena Klinovaja (Deputy Co-Director).

A total of 19 research group heads are involved: seven from the University of Basel, six from IBM Research – Zurich, four from ETH Zurich, and two from EPF Lausanne. In addition to the collaboration between academia and industry, the NCCR «SPIN» is characterized by very close links between theory and experimentation.

It brings together academic and industrial partners and combines knowledge gained over decades of research into quantum computers on the one hand, and into the miniaturization of silicon nanostructures on the other. The NCCR «SPIN» team consists of experts from various disciplines, such as quantum physics, engineering sciences, computer science and materials science.