Scalable implementation of hybrid spin qubits in CMOS-compatible devices

A quantum computer will solve problems that are impossible even for classical supercomputers to solve in reasonable time. Theoretical studies have indicated an expected "quantum speed-up" over classical computers in applications such as cryptography, optimization and simulation. However, to achieved this quantum speed-up requires large number of accessible qubits with extremely high fidelity. Current quantum technology offered few tens of qubits with barely satisfactory multi-qubit gate fidelity, and still it faces scaling up issues both in qubits as well as in peripheral control circuitry. Researchers have demonstrated qubits constructed from the spin states of impurity donors or quantum dots in silicon(Si) substrates with record-high coherence times. Meanwhile, Si-based qubits could potentially scale up benefiting from the standard industrial complementary metal oxide semiconductor (CMOS) processes. CMOS processes have been developing for the past few decades and state-of-art process can produce billions of transistors within a cm-scale chip. Therefore, silicon spin qubits are very promising candidates for quantum computing based on its robust storage of quantum information and possibility to leverage mature manufacturing processes. This project will investigate a possible spin qubit implementation based on silicon Nanowire Field Effect Transistors (Si NW-FETs). Quantum dots, or potentially donors located within the FET channel, will be used as the qubits, and strategies for using global control to improve scaling will be investigated. Qubit coupling using floating gates will be evaluated, and techniques to achieve high-fidelity spin read-out using reflectometry will be optimised.

Quantum technologies promise a transformation of the fields of measurement, communication and information processing. They present a particular opportunity since they are disruptive technologies: not only do they offer a chance for rapid growth but they also allow lesser participants in a field (such as the UK in IT) to become major players through appropriate risk-taking and manpower development. Students graduating from the InQuBATE Skills Hub will have the right mindset to work in the industries where quantum technologies will be applied, and help to break down the traditional barriers between those sectors to make this transformation happen. They will have all the necessary technical and transferable skills, plus a network of contacts with our partners, their fellow cohort members and the academic supervisors.

Our commercial partners are keen to help our students realise their potential and achieve the impact we expect of them, through the training they offer and their contributions to the centre's research. They include companies who have already developed quantum technologies to products in quantum communication (Toshiba) and optimization (D-Wave), large corporates who are investing in quantum technology because they see its potential to transform their businesses in aerospace, defence, instrumentation and internet services (Lockheed Martin, Google,) and government agencies with key national responsibilities (NPL). We want to see the best communication of our students' research, so our students will benefit from the existing training programme set up with a leading scientific publisher (Nature Publishing Group); we also want to see more of the future companies that lead this field based the UK, so we have partnered with venture capital group DFJ Esprit to judge and mentor the acceleration of our students' innovations toward the market.