Scalable quantum computers through cryogenic 3D nanoelectronics

The potential of quantum computers lies in their so-called quantum bits, qubits for short. There are different types of qubit technologies available today, all facing the same difficulty: Their states are very unstable. To ensure that they remain controllable long enough to perform computations, they must be cooled to extremely low (cryogenic) temperatures below -270°C. In order to connect large numbers of qubits to the necessary readout and control electronics, electronic components are required that can operate at extremely low temperatures without disturbing the quantum states.

The Fraunhofer Institute for Applied Solid State Physics IAF is researching innovative components for quantum computers together with eight partners in the EU project “SEQUENCE – Cyrogenic 3D Nanoelectronics”. The aim is to develop cryogenic electronics within three years that will make it possible to significantlyincrease the number of usable qubits in a quantum computer. With the help of electronics that can work directly on the cooled qubits, it should be possible in future to do without long connecting cables and elaborate setups. For the development of the planned electronics, the consortium combines competences from universities, research institutes and industry in the fields of Si-CMOS, III-V and 3D integration technologies. Other areas such as space communications and high-performance computing systems will also benefit from this research. 

Low-noise cryogenic electronics by Fraunhofer IAF

To ensure that the sensitive quantum states are not disturbed, electronics used in the immediate vicinity of qubits must not only be compatible with operation at low temperatures, but also feature extremely low noise and negligible heating. The many years of experience of Fraunhofer IAF in the field of cryogenic electronics for radio astronomy provide the perfect foundation for the ambitious project. The institute has the necessary expertise and low-temperature measurement technology to optimize its ultra low-noise high-frequency electronics for use in quantum computers. For this purpose, the chip size of the amplifiers and switches must be reduced via 3D integration and the noise must be improved even further, close to the limits of what is physically possible.

This project is receiving support by the European Union under grant agreement number 871764.