2019 Green Templeton Outreach Talks begin with exploration of quantum computing
The first talk in 2019’s Green Templeton Outreach Talk series was called, ‘Quantum computing – why you should be interested (and why not)’, and delivered by Carlos Outeiral, DPhil student at the Networked Quantum Information Technologies Hub, who also organized the series.
Carlos reports from the evening:
On Friday 15 May I had the privilege to deliver the first of the Green Templeton Outreach Talks. This series of talks is an initiative where PhD students can introduce their discipline to an inexpert audience, beyond the traditional “ivory tower research talks” that are practised in a typical doctoral programme. In this first edition I attempted to explain the central topic of my PhD project – quantum computing – and provide an overview of foreseeable impacts of this technology.
The talk started by introducing why computers are so important. In the world of big data and fake news, we are already attentive of how digital technologies are changing our society. Less obvious is perhaps the impact that computer power has had in our science and technology. For example, computer models are integral to modern engineering: long before an airplane (or a car) prototype is produced, engineers will have thoroughly tested structural resilience and aerodynamics with powerful computer simulations. Similar methods are used in fields so unalike as drug design and weather forecasting, and even problems like logistical planning strongly benefit from computer power.
The impact of computers is so deep that many technological limitations are in fact computer limitations. There are many problems that seem impossibly difficult to solve, in terms of the time it would take to reach a reasonable solution. An entire branch of computer science, known as computational complexity theory, is devoted to understanding the different complexities of solving computer problems. The great revolution came in 1995, when MIT mathematician Peter Shor showed how to solve a problem previously believed to be unsolvable (prime number factorization) could actually be solved very efficiently… if one could use a very special kind of computer, that behaved according to the laws of quantum mechanics.
Explaining how quantum computers work is bound to be complicated, and a rigorous discussion is out of place. The key idea is that quantum objects can be in several states at the same time, just as the celebrated Schrodinger’s cat, a well-known thought experiment of quantum mechanics, can be dead and alive simultaneously. One interpretation of this phenomenon, not to be taken literally, is that quantum objects exist as an “intersection of possible universes”. In particular, when we look at them (when we open the box of Schrodinger’s cat), we produce a splitting of the multiverse, and observe the results of one of the possible, parallel universes.
Quantum computing leverages parallel universes to do computation. For example, one may take Schrodinger’s cat and define the “dead” and “alive” states as “0” and “1”, and build a system of tools to manipulate them, just like a classical computer does. However, with enough ingenuity, the system can harness quantum effects to do computation well beyond what is possible classically. A key step of a quantum algorithm is that parallel universes must interfere, to ensure that the results can be read in any of the possible universes. The notable difficulty of this last step is probably the reason why only a handful of quantum algorithms are known.
David Deutsch, an Oxford physicist who made foundational contributions to quantum information technology, described a quantum computer as:
«[a device] capable of distributing components of a complex task among vast numbers of parallel universes, and then sharing the results.» (David Deutsch, The Fabric of Reality)
This discussion leads to a fascinating question that is at the heart of this talk: what is a quantum computer good for? We explored three areas where this technology is expected to make a difference.
The first area is cryptography. Although quantum computers will make standard encryption methods obsolete, they also promise truly secure information by implementing an unbreakable cryptographic protocol – the one-time pad. While shatterproof, this method is impractical: at the start, it requires that the interlocutors can exchange a message (the key) in perfect secret, defeating the purpose of cryptography in the first place. During the Cold War, the telephone line between Washington and Moscow used this protocol, after military couriers had delivered the keys. Quantum technologies promise to grant universal access to this level of security.
The second area is chemical discovery, or the tailored design of materials and pharmaceuticals by efficient computational simulation. Modelling a chemical substance is an arduous task: electrons, the particles that govern chemical behaviour, can be in several places at the same time, and this multilocation leads to an unmanageable number of equations. However, quantum computers can leverage their inherent quantumness to model electrons very efficiently, and it is expected that they will revolutionise how chemical and pharmaceutical research is done.
The final one is logistic design, including problems like resource allocation, scheduling or route planning. Most of these problems are notoriously hard, and all the solution methods are heuristic, meaning that they are not guaranteed to produce the “best” solution. Significant research efforts have attempted to find quantum heuristics that improve over classical methods. Unfortunately, although part of the scientific community expects quantum computing to make progress in this field, there are still no definitive results.
The promises of quantum computing are manifold. Unfortunately, the development of actual quantum computing hardware is lagging behind. The largest quantum computer disclosed to date is Google’s Bristlecone processor, with 78 qubits. In comparison, it is estimated that superseding a classical supercomputer using Shor’s algorithm would take anywhere between tens and hundreds of millions of qubits. Given the difficulties of producing quality qubits, their instability and their exorbitant prices, it is unlikely that revolutionary applications are possible soon.
This fact will not make quantum computing any less interesting. Given the enormous amounts of computational power that it would unlock, and the multiple problems that it promises to solve, it is unsurprising that both public and private sectors are investing heavily in developing this emergent technology. However, while its impact is undeniable, we may still need to wait several decades until we can build a quantum computer capable of truly making a difference.
Find out more about the 2019 Green Templeton Outreach Talks.
Upcoming talks in this series:
Talk 4: Thursday 27 June, 17.30
Should we vaccinate children against addictions? Some ethical considerations
Speaker: Lovro Savić, PhD student in Public Health Ethics, University of Oxford
More information and register here
The fast-paced technological development in the last decades has brought many crucial ethical questions to the table. Many of these questions are as fascinating as they are difficult, creating strong controversies both in the medical profession and public opinion. How do we find solutions? How can we understand what is right? In this talk, Lovro Savić, PhD student in Public Health Ethics at the University of Oxford, will provide a gentle but captivating overview of public health ethics, explaining how researchers study these questions and try to come up with useful solutions. In particular, Lovro will be examining a real-life research question: is state-mandated vaccination of children against addictions morally admissible?
Previous talks in this series:
Talk 2: Friday 31 May, 17:30
Big data – big deal?
Speaker: Rosemary Walmsley, PhD student, Big Data Institute
Read a full report from the evening
The age of big data, and the machine learning tools accompanying it, has not left anyone untouched. This technology has shaken our economical and political landscape, impacting everything from our personal lives and how we interact with our environment, to policy decisions of all kind. But what is actually new? How is it actually changing our world? And, more importantly, how much of it is just hype? In this talk, Rosemary Walmsley, PhD student at the Big Data Institute, University of Oxford, will provide an accessible introduction to big data and machine learning, and facilitate a discussion of this, aiming to build critical engagement with big data and machine learning.
Talk 3: Monday 10 June, 17:30
Introducing the economics of happiness
Speaker: Karl Overdick, PhD student in Management, University of Oxford
In the last decades, a new field of economics has been built upon the principle that everyone tries to be as happy as they can be, aiming to quantify and study happiness, as well as trying to understand what can be done to maximise it from the personal and policy point of view. In this talk, Karl Overdick, PhD student in Management at the University of Oxford, will provide an introductory and balanced view of what the field of subjective wellbeing has found in the last few decades since its inception.
For more information about the GTC Outreach Talks please contact:
Carlos Outeiral
carlos.outeiral@gtc.ox.ac.uk
