Our vision is to enable the world of quantum computing through an unprecedented stable and scalable many-qubit system, which will be developed by TOPSQUAD. This platform will allow us to establish important scientific breakthroughs such as the observation of Majorana bound states, which can lead to a new field in physics: non-Abelian many-body physics.
Among different kinds of quantum computers, the universal quantum computer is the most powerful and the most general one, and can be exponentially faster than classical computers for certain scientific and technological applications. This long-awaited innovation can help solve many global challenges of our time related to health, energy and the climate, such as quantum chemistry problems in order to design new medicines, material property prediction problems for efficient energy storage, big data handling problems, needed for complexity of climate physics. However, such a quantum computer has not yet been realised. There are two key reasons:
1. Qubit fragility: current qubit architectures are too fragile to withstand interference from the environment (e.g. noise). This ‘quantum decoherence’ means destruction of the information of the qubits and thus poses a tremendous challenge to build a system of thousands of coherent logical quantum bits.
2. Qubit scalability: the qubit architecture is not scalable enough: the required number of qubits for a universal quantum computer is far out of reach for all proposed quantum systems, including superconducting qubits, ion trap qubits and spin qubits. Depending on the qubit type and architecture, the estimated minimum number of building blocks varies from 10 thousand up to 100 million. The most successful platforms can make between 10 and 100 quantum bits.
The approaches have not been combined within a single system, but our recent results show that we can address these challenges: we will develop topological protection in a scalable CMOS-compatible platform by creating the first topological states in a germanium-silicon material system: Ge wires. We will combine the waferscale nanofabrication skills of the consortium with our individual Ge wire research into reproducible Ge wires grown on Si wafers. We will validate the potential and utility of this system, by showing that it can answer current and emerging scientific questions. We will e.g. investigate fundamental issues such as proximity-induced superconductivity in different semiconductor wires, and one of the hottest topics in modern condensed matter physics: Majorana Bound States.