The physical implementation of logical qubits using trapped ions

Fault tolerance is a key step toward the construction of a large-scale quantum computer. Without fault tolerance,
small infidelities in quantum gates accumulate over the course of an algorithm, limiting the size of computations
that could be performed. While the no-cloning Theorem ruled out the naive implementation of classical correction
schemes, new ones such as the Steane code were developed. An important notion associated with quantum error correction
codes is the logical qubit. Detecting and correcting errors is achieved by using multiple physical qubits to form
a smaller number of robust logical qubits. The physical implementation of a logical qubit requires multiple qubit and
the ability to perform high fidelity gates on them.
The project aims to realize a logical qubit based on ions confined on a microfabricated surface trap and use the
system to correct for multiple errors. This project will make use of concepts that have already been demonstrated
and currently are under development at the Ion Quantum Technology Group at Sussex. Each physical qubit will be
a microwave dressed state qubit based on ytterbium ions, trapped on a microfabricated surface trap. The surface trap
will consist of an X-junction geometry. Gates will be realized through RF and microwave radiation in combination
with magnetic field gradients [1]. The implementation of a logical qubit forms an integral part of the group's long term
effort to construct a large scale quantum computer as laid out in the blueprint published early 2017

The main impact of the proposed Hub will be in training quantum engineers with a skillset to understand cutting-edge quantum research and a mindset toward developing this innovation, and the entrepreneurial skills to lead the market. This will grow the UK capacity in quantum technology. Through our programme, we nurture the best possible work force who can start new business in quantum technology. Our programme will provide multi-level skills training in quantum engineering in order to enhance the UK quantum technologies landscape at several stages. Through the training we will produce quantum engineers with training in innovation and entrepreneurship who will go into industry or quantum technology research positions with an understanding of innovation in quantum technology, and will bridge the gap between the quantum physicist and the classical engineer to accelerate quantum technology research and development. Our graduates will have to be entrepreneurial to start new business in quantum technology. By providing late-stage training for current researchers and engineers in industry, we will enhance the current landscape of the quantum technology industry. After the initial training composed of advanced course works, placements and short projects, our students will act as a catalyzer for collaboration among quantum technology researchers, which will accelerate the development of quantum technology in the UK. Our model actively encourages collaboration and partnerships between Imperial and national quantum tehcnology centres and we will continue to maintain the strong ties we have developed through the Centre for Doctoral Training in order to enhance our on-going training provisions. The Hub will also have an emphasis on industrial involvement. Through our new partnerships students will be exposed to a broad spectrum of non-academic research opportunities. An important impact of the Hub is in the research performed by the young researchers, PhD students and junior fellows. They will greatly enhance the research capacity in quantum technology. Imperial College has many leading engineers and quantum scientists. One of the important outcomes we expect through this Hub programme is for these academics to work together to translate the revolutionary ideas in quantum science to engineering and the market place. We also aim to influence industry and policy makers through our outreach programme in order to improve their awareness of this disruptive technology.