Building and exploiting a high-performance monolithic trapped-ion quantum computer

This project is aimed at developing the world's highest-performance quantum processor - a new form of computer that manipulates information in a vastly different and more powerful way than a conventional computer. Sufficiently large quantum computers can solve problems intractable on any type of non-quantum ("classical") hardware. For example, a quantum computer would be able to simulate the physics or chemistry of complex problems impossible to model on a classical super-computer. This would profoundly impact scientific research, and allow access to regimes that are currently beyond experimental or theoretical reach; for example in quantum chemistry, or condensed matter physics. Despite 20 years of experimental work on quantum computing, a quantum processor with such computational power has remained beyond the reach of experiments. Recent progress in trapped-ion techniques means that such a machine is now attainable in the time-frame of this project.

In recent years a variety of technologies has been used to show that the building blocks of a quantum computer can work well enough to perform useful real-world computations. The challenge now, for all technologies, is to develop systems with a large number of qubits (quantum bits, the basic unit of information in a quantum computer) possessing the qubit-to-qubit connectivity which is essential for quantum computing, while minimizing operation errors. The eventual aim for this field is to build processors containing hundreds of thousands of effectively perfect qubits all connected by high precision quantum logic gates. Such a full scale quantum computer will change the 21st century in the same way as the classical computer changed the 20th century. However, building a processor this complex remains a formidable engineering challenge which will require significant resources and last for decades.

The focus of this project is instead to try and aim for a realistic near-term goal. Using trapped atomic ions as qubits, and taking advantage of the high fidelity and high connectivity gates already proven with these qubits, we aim to make a processor with at least 50 qubits, with gate errors low enough to perform circuits of thousands of gates. Such an intermediate scale quantum processor is beyond the ability of even our most powerful classical supercomputers to mimic. With this processor, we aim to demonstrate the potential quantum computers have to solve real-world problems with a "quantum advantage". In addition, we aim to develop and to test noise-resilient methods to extract maximum performance from intermediate-scale processors, such as error mitigation protocols and hybrid quantum-classical algorithms. However, as the history of classical computing has shown us, with the ability to develop and to prototype new techniques on real quantum hardware the largest rewards may well come from unexpected directions. This project will deliver that hardware.

All current computers use the principles of classical physics for their operation. However, the fundamental rules of nature are quantum mechanical. A quantum computer is the most powerful way of processing information that the laws of physics permit. The long-term impact of quantum computing will be a dramatic shift in how information is processed: a large quantum computer will change the 21st century in the same way as the classical computer changed the 20th century.

The aim of this Fellowship is to develop an intermediate-scale quantum computer that is powerful enough to solve problems that current computers cannot. The results of this Fellowship will have an impact on:

The Economy: this new way of computing requires development of quantum hardware and software - this will create new markets for the already large IT sector of the UK economy. Trapped-ion qubits also rely on optical (laser) methods for their manipulation, which links well to the UK's world-leading photonics industry.

Industry and Commerce: Quantum computing will have direct impact on any industry that requires understanding the behaviour of quantum mechanical systems, as quantum computers provide a way to efficiently simulate these systems - these include the pharmaceutical industry and the chemical industry. There will also be longer-term impact on a wide-range of industries that require information processing, from speed-ups in optimisation, machine learning, and forecasting. In the short term this project will generate valuable IP which will protected and exploited, either via licensing or via a spin-out company with guidance from Oxford University Innovation.

The Public: The new ways to process information enabled by quantum computing will have long-term socio-economic impact. Quantum simulation will enable development of new and improved pharmaceuticals, which will treat new diseases and reduce side-effects. It will also enable development of more effective industrial processes, for example improving the synthesis of fertilisers, reducing the associated energy cost and pollution.

People: This project will help to train the next generation of quantum scientists. These scientists will have the skill-set required to drive forward the nascent quantum technologies industry. Furthermore, these scientists will have wide-ranging skills and experience that equips them to make leading contributions to many areas of industry and science. These skills include software engineering, electronic and optical design, and high-level simulation and data-analysis.