Challenges for Quantum Computer Science & Simulation Workshop Report 1 October 2017

Challenges for Quantum Computer Science & Simulation Workshop Report

1 October 2017

Summary

Recommendation 6 of the ‘Quantum Age’ report 2016 (Government Office for Science) states that:

“The National Quantum Technologies Programme should work with the Alan Turing Institute, the Heilbronn Institute for Mathematical Research and wider academia to identify a set of example challenges which, if solved by a quantum computer or quantum simulator, would have important benefits to government, business and citizens.”

In response to this, EPSRC held a workshop on “Challenges for Quantum Computer Science and Simulation” bringing together wider academia to discuss the role of quantum computing and simulation in addressing future opportunities and challenges in ICT.

Background

Steady improvements in information and communication technologies have been a fundamental driver of economic and social change since the 1950s. However, this assumption is now threated by a slowdown in the previously exponential growth in the computing capability (associated with ‘Moore’s law’) together with an exponential growth in data. Quantum computing provides a fundamentally different approach to processing information and has the potential to surpass conventional computers in searching large datasets, factoring large numbers and simulating chemical and biological systems. This raises the prospect of improvements to data analytics, drug development, logistics and materials design; new insight into biological systems; and wide-ranging security implications as common cryptographic approaches are made obsolete. However, the potential for quantum computers to outperform conventional computers is currently unclear beyond a small number of applications.

Rapid progress in the realisation of various platforms for producing and manipulating units of quantum information (‘qubits’) has been made in recent years. The UK has a leading position in developing a number of these platforms, drawing on its strong research base and investment made through the UK National Quantum Technologies Programme. While the realisation of large-scale quantum computers remains some way off, many researchers believe that small-scale (50-100 qubit) systems that are capable of complex simulations will be available within a decade.

As developments in quantum computing hardware continue to gather pace worldwide, many research groups are focussing on the ultimate goal of engineering a universal large-scale quantum computer. Keeping pace with these developments and understanding the capabilities of quantum computers will require fundamentally rethinking ‘classical’ computer science, requiring research into new algorithms, programming languages and methodologies for error detection and correction. To focus these efforts, and ensure that quantum computing is well-integrated within the wider engineering and physical sciences research landscape, we propose facilitating the identification of specific challenges that would benefit from the development of quantum computers/simulators and have high commercial and societal value to the UK.1

Workshop Objectives and Format

On 30 March 2017, EPSRC held a one-day workshop at the Mercure Holland House Hotel, Bristol. In order to encourage the development of a community of practice around the challenges that are identified and encourage new approaches, EPSRC encouraged contributions from a wide range of research disciplines and at different career stages. Attendees were selected on the basis of Expressions of Interest to attend (assessed by EPSRC staff). In addition a number of places were made available to key stakeholders, such as the Alan Turing Institute, Heilbronn Institute, the Quantum Technology Hubs, and EPSRC Quantum Technology Fellows (see Annex 1 for a full list of attendees). The objectives of the workshop were to: • Discuss the role of quantum computing and simulation in addressing future opportunities and challenges in ICT. • Discuss the expertise required to address these challenges and identify areas where further collaborative work is required in order to make progress. • Identify and prioritise specific research challenges that: o could realistically be addressed by envisaged developments in quantum computing and simulation; o will have significant economic and societal value to the UK; o contribute to and/or draw-upon strengths in UK academia, industry and/or government; and o provide a focus to enable stronger working relationships across disciplinary boundaries.

1 This is proposed in recommendation 6 of the recent ‘Quantum Age’ report (2016, Government Office for Science) During the workshop, participants had the opportunity to contribute input via a number of facilitated sessions. These started by considering the requirements of potential users of quantum computing and simulation, and then moved on to explore and develop challenges resulting from the insights gained by considering these user perspectives. This was followed by an opportunity to hear the perspective of 4 speakers who were invited to share their perspective on the current state of the art and likely developments in the field over the next 5 years, as well as offer a general perspective on the role of quantum computing in addressing wider challenges. During the final session, participants had the opportunity to provide further input into the challenges identified earlier in the day (see Annex 2 for further details of the agenda).

Workshop Findings

In advanced of the meeting, participants were invited to submit a response to the question: ‘what do you think will be the most significant impact resulting from developments in quantum computing and simulation over the next 5 years?’ and perform a clustering of the responses using the Well Sorted online tool (see Annex 3 for full details).

At the start of the workshop participants were invited to split into a number of different groups based on the clusters that had been identified. Participants were then asked, within their groups, to consider a scenario from the perspective of a hypothetical user of quantum computing / simulation. The groups interpreted a ‘user’ as a researcher, developer or student based in an academic, industrial or governmental institution. During this first session, the participants were invited to consider the hopes, fears and needs of their hypothetical user(s), and capture any insights arising (summarised in Table 1 below).

Hopes Fears • Simple, accessible and affordable • Users do not engage as they are systems that have the capability to waiting for the perfect platform. solve difficult problems. • Platforms robust to noise fail to • An enabler of adventurous research. emerge. • Emergence of platforms which are • Quantum systems do not provide robust to noise. the expected speed boost. • Systems that provide a competitive • Expectations are unrealistically high advantage. and lead to disappointment. • No quantum knowledge required for • Viable supply chains fail to emerge, users. leading to ‘dead ends’ and/or • New algorithms enable what is monopolies. currently impossible. • Software engineering remains • Accept that early hardware will be immature. imperfect and make the most of it. • Privacy concerns inhibit the take-up of quantum systems. Needs Insights • Road-mapping. • There are a wide range of potential • Identify what can’t be done early users and a careful process of on. prioritisation is necessary to focus • Focus on valuable problems that on engaging with groups of users to require a performance edge and accelerate progress. Building those with an appetite for risk. confidence in the nascent • Verification and certification of technology is crucial. performance. • Expectations need to be managed • Abstract away the physics; keep the carefully. The term ‘quantum power. supremacy’ was considered to be a • Demonstrate the possibility of large particular example of unhelpful scale operation. terminology. • Training for potential users. • The development of ‘classical computing’ provides many useful lessons – not least with respect to the emergence of competing platforms - and ‘classical’ and quantum approaches should be seem as complementary. • Quantum as a service/in the cloud is a particularly promising approach.

Table 1. Summary of group activity to identify the hopes, fears and needs of hypothetical user(s) of quantum computing/simulations, and related insights.

In the final session of the morning the groups of participants were invited to consider the insights they gained during the previous discussion to start exploring potential research challenges by developing and prioritising ‘problem statements’. They were then encouraged to generate and cluster initial ideas for research challenges relevant to the problem statements. Key themes that were addressed by multiple groups at this stage of the workshop included:

• Removing barriers to engagement with the wider ‘classical’ computer science and engineering communities, for example by developing toolkits and cloud-based approaches. • Roadmapping as a tool for user engagement, particularly in matching users to the capabilities of specific platforms that are under development. • Ensuring that quantum platforms are trustworthy to their users. • Taking into account user requirements when considering the trade-off between a focus on modularity/scalability and the refinement of small- scale systems.

At the start of the afternoon session, participants had the opportunity to hear short talks from four speakers2 who shared their perspective on the current state-of-the-art and likely developments in quantum computing and simulation over the next five years, followed by a question and answers session.

2 Prof. Harry Buhrman (QSoft, Amsterdam), Prof. Elham Kashefi (University of Edinburgh), Dr. Viv Kendon (Durham University) and Dr. Chris Doran (ARM Ltd). During the final session of the workshop, participants were encouraged to revisit the initial ideas for research challenges that were discussed in the morning and then break-out into groups to develop them in further detail.

Following the workshop, EPSRC staff reviewed the participant’s input and grouped it under the following three headings to reflect the issues raised:

1. Building confidence and capacity in the UK’s quantum computing and simulation community

Participants highlighted the importance of widening engagement beyond the existing ‘quantum’ research community in order to build the multidisciplinary teams required to make progress. This was considered equally important for continued technological progress and also developing a common language that will build a wider understanding of quantum approaches. The importance of managing expectations and careful use of terminology to avoid hype was noted, as was the importance of tailoring training approaches and supporting those wanting to move into the field of quantum computing/simulation.

Development of the UK’s quantum supply chain was also considered a high priority, requiring an in-depth understanding of the requirements and prejudices of users, as well as visible role models. Faced with the vast range of potential uses of quantum computing/simulation, a rigorous process of prioritisation will be necessary to focus effort on forming collaborative relationships that drive demand.

2. Preparing for disruption The disruptive nature of quantum computing/simulation – and indeed other post-CMOS approaches – is expected to have a significant socioeconomic impact. Participants discussed the lessons learned from the emergence of classical computing and importance of developing roadmaps and mechanisms that provide tools for engagement and build the confidence of investors. Participants noted the benefit in identifying early adopters with a high appetite for risk and finding opportunities to get technology into their hands as quickly as possible, since this will stimulate innovation.

Approaches to identifying and quantifying the technological thresholds that will lead to significant breakthroughs are required, particularly where these developments are anticipated to lead to significant changes. The impact of quantum computation on encryption was discussed as an exemplar, with participants noting the need for researchers to follow the principles of responsible research and innovation, and engage proactively in the development of timely regulatory and standards regimes.

3. Matching users to quantum solutions Participants noted that the wide range of competing architectures currently under development presents challenges and opportunities. It is unlikely that a single approach will be the best solution for every application, but investment over the next five years is likely to ‘lock in’ certain aspects of the technology and its supply chain. Making informed decisions will require those working on the development of hardware and software aspects to work closely with each other and users.

A clear understanding of the commercial drivers of potential applications (i.e. problems where a user is prepared to pay for an answer), identification of beneficiaries, and the development of approaches to ensure robust verification of reliability and performance, were seen as important enablers. Participants noted that there were many valuable problems that could be addressed without a large-scale fault tolerant quantum computer. Analogue quantum simulators and other devices not based on standard qubit architectures may provide interesting opportunities for rapid progress in hardware and software development.

Next Steps

• Exploring with the research community what the research and innovation challenges are to building confidence and capability and establishing quantum computer science and simulation technologies. • Research community engagement in the public dialogue and other responsible research and innovation efforts. Engaging with the research community in relation to the outcomes of the public dialogue on quantum technologies. • Involve end users of quantum computer science and simulation in activities to build confidence in the technologies and enable the matching of users to quantum solutions.

Annex 1 – Workshop Attendees

Challenges for Quantum Computer Science & Simulation Workshop Thursday 30 March 2017 Mercure Holland House Hotel, Bristol

Attendee List

Richard Banach Manchester Simon Benjamin University of Oxford Harry Buhrman Qsoft (NL) Wendy Carr EPSRC James Cawley TRL Iris Choi University of Oxford Andrew Daley Strathclyde Chris Doran ARM Ross Duncan Strathclyde Mark Everitt Loughborough Antonio Andreas Gentile UniBristol Lilia Georgieva Heriot-Watt University Richard Gunn EPSRC Niki Haines Keysight Technology Winfried Hensinger Sussex Derwen Hinds NCSC Chengyong Hu E&E, University of Bristol Theodoros Kapourniotis Warwick Elham Kashefi University of Edinburgh Viv Kendon Durham University Myungshik Kim Imperial College London Anthony Laing Bristol Samantha Lichey TRL Noah Linden University of Bristol Graham Marshall University of Bristol Andy Mason D-Wave Christopher Maynard Met Office Richard McCracken Heriot-Watt Univeristy Ashley Montenaro University of Bristol Sam Morley-Short University of Bristol Soon Xin Ng University of Southampton Helen Niblock EPSRC Joshua Nunn University of Oxford Dominic O'Brien University of Oxford Zlatko Papic University of Leeds Andrey Pepelyshev Cardiff University Dave Robertson Edinburgh Martin Sadler Independent Les Sims EPSRC Gary Sinclair University of Bristol Rupesh Srivastava NQIT - Oxford University Nathan Walk University of Oxford Cheryl Wise NCSC Graham Worth UCL Nelly Wung EPSRC Paul Yates TRL

Annex 2 – Agenda

Challenges for Quantum Computer Science & Simulation Workshop

30 March 2017

Mercure Holland House Hotel, Bristol

10:00 Registration & coffee

10:30 Welcome & introduction

Richard Gunn, EPSRC

10:45 Exploring use cases

11:35 Exploring challenges

Refreshments will be available at 11:40

12:15 Lunch

13:00 Quantum Computer Science & Simulation: where are we now?

Elham Kashefi; EPSRC Fellow, University of Edinburgh

Harry Buhrman; Executive Director, QSoft

Viv Kendon; EPSRC Fellow, Durham University

Chris Doran; Director Research Collaborations, ARM

14:00 Developing challenges

Refreshments will be available at 14:15

15:45 Closing remarks and next steps

Richard Gunn, EPSRC

16:00 Depart

Annex 3 – Pre-meeting Activity

Prior to the meeting, participants were asked to submit a single response to the following question:

“What do you think will be the most significant impact resulting from developments in quantum computing and simulation over the next 5 years?”

22 responses were received which the participants then clustered ahead of the meeting using Well Sorted.

The Well Sorted outputs are available to view at https://www.well- sorted.org/output/ChallengesforQCSSimulation/.