Features

It's that time of the year again when we look forward to the shrieks, bangs and 'aaaahhs' generated by the Oxfordshire Science Festival.

Oxford University staff and students are involved in many of the events taking place 6-21 March, with the regular Wow! How? science fair at the OU Museum of Natural History & Pitt Rivers (13 March) and the Oxford University Science Roadshow (15-19 March) amongst the sciencey enticements on offer.

As always Wow! How? (10am-4pm on the 13th) is all about hands-on science with fun experiments and demonstrations: expect custard, rockets, slime, explosions, and creepy-crawlies.

Although aimed at a family audience, the festival is free and open to everyone. The Wow! How? team are still looking for volunteers so if you are (or know) an Oxford scientist who would like to get involved email [email protected] or call 01865 282456.

Meanwhile, the Oxford University Science Roadshow continues to take the message that science can be fun out to schools around Oxfordshire.

This year's programme will see George McGavin introduce pupils at St Birinus School, Didcot to the world of insects (15th), David Pyle explore the hot stuff of volcanoes at Burford School and Community College, Burford (16th), Suzie Sheehy bring accelerated physics to Wood Green School, Witney (17th), Marcus du Sautoy present the number mysteries at St Gregory the Great, Oxford (18th), and pupils at Lord William's School, Thame find out about earthquakes from Tony Blakeborough (19th).

In all there are over 100 events happening as part of the festival that ties in with National Science and Engineering Week so, wherever you are, March should see great science events happening somewhere near you.

A team, including Oxford University scientists, recently used a quantum computer to calculate the precise energy of molecular hydrogen.

The breakthrough [more here], reported in Nature Chemistry, is the first step towards using one quantum system (in this case entangled photons) to model another (such as a chemical reaction).

I asked Jacob Biamonte from Oxford University's Computing Laboratory, an author of the paper, about the work and what harnessing such 'quantum simulations' might mean for science and even the conquest of space...

OxSciBlog: Why is calculating the precise energy of hydrogen so hard?
Jacob Biamonte: The equations that predict unknown properties of matter have been around for almost 100 years, if only we had a computer capable of solving them! Molecular hydrogen represents an excellent test case for a prototype dedicated quantum processor: a quantum chemistry simulator.

A future quantum simulator will help us understand the nature of matter - particularly chemical reactions - by finally providing solutions to long standing problems, that we simply have been unable to solve using even the world’s largest classical computers.

OSB: How can quantum computing help?
JB: The thought process of humans has evolved to reason in the world we live in. Although these effects are crucial to life itself, quantum effects are essentially unnoticeable in our day-to-day lives. Like the conscious thought process of our brain, machines that operate using 'classical sequences' face grave difficultly modelling systems, such as molecules, that operate by 'quantum sequences'.

Quantum sequences are not only difficult for our classical brains to understand, but at least very difficult and likely even impossible to accurately model using any device that operates by classical sequences. Quantum simulators overcome this problem as they naturally operate using quantum sequences - it is just up to our classical brains to ask them the right questions, and many of the most important ones are about quantum chemistry.

OSB: What was the biggest obstacle you had to overcome?
JB: Let's consider a classical sequence as an ordering of say a dozen events on a time line. These events are ordered in an obvious (classical) manner: the twelfth event depends on the eleventh down the line to the first, and so on. To get any idea of how much of an obstacle quantum mechanics is for our classical brains to understand, let's consider the quantum version of the same sequence of a dozen events:as a quantum sequence, the  first event on the time line can be made to depend on the twelfth event, occurring in the future! This is not Star Trek!

A few generations of scientists thought it was a 'bug' in quantum theory - first pointed out by Erwin Schrödinger in a paper he wrote during his time in Oxford about 80 years ago. 60 years later it was Oxford Professor David Deutsch who decided to turn this 'bug' into a feature, and said we should use it as a new powerful computational resource.

OSB: What does your project tell us about how 'quantum systems can help model quantum systems'?
JB: A date in history that some of us should experience in our lifetimes will be the day a quantum computer out-performs the world’s fastest classical super computer. It is almost certain the problem solved will be an intractable chemical simulation, such as the currently unattainable task of finding the ground state of even a modest molecule, like caffeine.

This represents a step forward that is difficult to imagine. What if we did not know how to control electricity, but had blueprints for iPhones, electric motors, and dishwashers? Material Scientists and Quantum Chemists are in this situation! The impact a quantum simulator will have on this world is as difficult to imagine as an iPhone would have been in the Dark Ages.

OSB: How do you hope to take this research forward?
JB: This research is important for the human species! We need to know things about matter that it seems only quantum computers will be able to tell us. This will take our science forward, turn our world into a super civilisation almost overnight, lead to rapid and wild advances in medicine, and likely lead to materials needed to construct spacecraft.

We are gathering synergy in the quantum computing research community, and more interest on using these devices as a tool to explore physics and chemistry. We have plans to start a webpage with experimental benchmarks, providing chemistry benchmarks to the small quantum processors of today, and leading up to an exact resource count for the first classically impossible calculation that a quantum simulator will solve. It's exciting, it's the future, and it's being built now!

Jacob Biamonte is based at Oxford University's Computing Laboratory

An exotic type of symmetry - suggested by string theory and theories of high-energy particle physics, and also conjectured for electrons in solids under certain conditions - has been observed experimentally for the first time. 

An international team, led by scientists from Oxford University, report in a recent article in Science how they spotted the symmetry, termed E8, in the patterns formed by the magnetic spins in crystals of the material cobalt niobate, cooled to near absolute zero and subject to a powerful applied magnetic field.

The material contains cobalt atoms arranged in long chains and each atom acts like a tiny bar magnet that can point either ‘up’ or ‘down’. 

When a magnetic field is applied at right angles to the aligned spin directions, the spins can ‘quantum tunnel’ between the ‘up’ and ‘down’ orientations. At a precise value of the applied field these fluctuations ‘melt’ the ferromagnetic order of the material resulting in a ‘quantum critical’ state.

‘You might expect to see random fluctuations of the spins at this critical point but what we uncovered was a remarkable structure in the resonances of the magnetic spins indicating a perfectly harmonious state,’ said Radu Coldea from Oxford University’s Department of Physics who led the team.

As the critical state was approached the researchers observed that the chain of atoms behaved like a ‘magnetic guitar string’.

Radu added: ‘The tension comes from the interaction between spins causing them to magnetically resonate. We found a series of resonant modes. Close to the critical field the two lowest resonant frequencies approached closely the golden ratio 1.618…, a characteristic signature of the predicted E8 symmetry.’

He is convinced that this is no coincidence and it reflects a subtle form of order present in the quantum system.

The resonant states seen experimentally in cobalt niobate may be our first glimpse of complex symmetries that can occur in the quantum world. “The results suggest that similar ‘hidden’ symmetries may also govern the physics of other materials near quantum critical points where electrons organize themselves according to quantum rules for strong interactions,’ Radu told us.

The research was supported by EPSRC and Radu aims to use a new EPSRC grant to explore the physics of materials near quantum criticality.

The team included Dr Radu Coldea, Dr Elisa Wheeler and Dr D Prabhakaran from Oxford University’s Department of Physics, as well as researchers from Helmholtz Zentrum Berlin, ISIS Rutherford Laboratory, and Bristol University.

At the current growth rate the global population is predicted to reach 10 billion by 2050. To feed this many people, food production worldwide will need to double during a period when climate change will worsen, fossil fuels will dwindle, and water availability will become unpredictable.

In addition, if we are to protect what biodiversity we can, this doubling of agricultural output must take place using the same amount of farmland, without impacting upon remaining natural habitats.

To tackle this problem, scientists in Oxford University’s Department of Plant Sciences are aiming to develop high-yield crop strains which will be better adapted to this climate-altered, resource-poor agricultural landscape of the near future.

Boosting rice crops
Professor Jane Langdale, Head of the Department of Plant Sciences, is engaged in the ‘C4 Rice’ project, an international effort funded by the Bill & Melinda Gates Foundation [more here]. 700 million people in Asia currently depend on rice for the bulk of their calorific intake and it is predicted that during the next 40 years, rice production needs to increase by 50 per cent in order to feed the growing Asian population, whilst adapting to adverse changes in climate and water availability.

Photosynthesis converts carbon dioxide and the energy from sunlight into chemical energy and takes place in cell organelles called chloroplasts. The chemical energy produced in these chloroplasts is then used by plants to live, grow, and in the case of crops, produce grain.

Conventional rice varieties use a standard photosynthesis pathway known as ‘C3’, but under certain conditions, such as warmer temperatures, this pathway is inefficient. A number of plants, including maize, have evolved an extra photosynthesis pathway, called ‘C4’, to solve this problem. The C4 photosynthesis pathway can increase efficiency by 50 per cent and introducing it into rice could provide the answer to Asia’s impending food problem.

The C4 Rice project is often quoted as being ‘highly ambitious’. In order to work, large changes need to be made to both the anatomy of rice leaves and the chemical reactions that take place inside them. However, there is encouraging evidence that it could be done.

Jane’s work on the GLK genes suggests that they may play a role in regulating whether a plant’s chloroplasts use C3 or C4 photosynthesis. Ongoing work in her laboratory seeks to put GLK genes from maize, a naturally C4 crop, into rice plants. Her work on chloroplasts began due to an interest in the genetic control of development in plants, rather than a specific aim to put C4 photosynthesis into other plant species. Whilst developing new C4 crops had always seemed like an interesting idea, she never thought it would be realistic.

20 years of chloroplast research later, Jane was ready to move into new research areas. It was at this point, in 2006, that the International Rice Research Institute (IRRI) invited Jane to a C4 Rice Consortium workshop. Originally reluctant to go, she was persuaded to attend by Julian Hibberd from the University of Cambridge, and found herself getting excited by the proposed project. She is now 5 months into a 3 year “proof of concept” project involved in testing the feasibility of C4 Rice, a necessary step called for by a paper in Current Opinions in Plant Biology written with Julian and John Sheehy from IRRI last year.

Using less fertiliser
As well as facing climate change, 21st century agriculture will also have to cope with the decline in fossil fuels. The work of Oxford’s new Sherardian Professor of Botany, Liam Dolan, aims to produce crops which grow healthily without excessive phosphate-rich fertiliser application.

Phosphate is required by all living organisms to build cellular components and the low availability of phosphate in natural environments can severely limit plant growth. The soil of all of sub-Saharan Africa and one third of China is deficient in this crucial nutrient. The application of artificial fertilisers all over the world has so far dealt with this problem and contributed to the increase in productivity seen in the Green Revolution of the 20th Century.

Phosphate is extracted from mines, mainly in Morocco, the USA, China, the Former Soviet Union and South Africa, with 80 per cent of the phosphate produced being put into fertilisers. The extraction and transport of phosphate for agricultural use constitutes a considerable annual cost and carries a large carbon footprint. Furthermore, like oil, phosphate reserves are finite, and some predictions claim that phosphate mines could be exhausted within the next 30 years.

Liam’s work aims to develop crops which are better adapted to scavenge their own phosphate from the soil, making them less dependent on artificial fertilisers.

Plants can naturally extract their own phosphate from the soil using root hairs, single-cell structures which grow along roots. Liam’s research group have discovered a family of genes which control root hair growth and they are working to modulate the expression of these genes in crop plants. Their aim is to increase the number of root hairs a plant produces in response to naturally occurring phosphate in the soil. They have developed transgenic wheat and rice varieties capable of producing longer root hairs and are now moving on to field experiments to test the yield of these plants in the absence of commercial fertiliser.

Unlike Jane Langdale’s chloroplast work, this has always been the aim for Liam. He jokes that his team are now finally at the stage he had hoped to be at by the end of his PhD, explaining that this has been a very large project, starting from scratch and requiring the discovery of all the necessary genes involved.

Planning for 21st Century
In light of the global food security crisis we will soon be facing, the University’s Department of Plant Sciences will next year be launching a 21st Century Crops research initiative. This initiative seeks to found an Oxford Professorship in Crop Science and to encourage translational research, so that discoveries made about plant metabolism, growth and development can be transferred to agriculturally valuable crop plants.

However, both Jane and Liam believe that whilst plant science has a lot to offer in solving the food security challenge, the role of governments and funding bodies is crucial, a point that was emphasised at the 'Food Security in the 21st Century' Symposium hosted by the Department’s graduate students last October.

Due to the unequal distribution of global wealth, the countries facing the most immediate problems do not have the funds to overcome them. Jane argues that to tackle food security there must be sustained funding and input from wealthy countries in order to bring about developing nation benefits. Liam points out that every day the same number of people die from malnutrition as from cancer, reflecting the bias of interest in developed countries. However, whilst scientific research alone cannot solve the issue of food security in the face of global politics, it is, says Jane, a very exciting time to be a plant scientist. 

Penny Sarchet is based at Oxford University's Department of Plant Sciences

To celebrate BBC Year of Science 2010 three Oxford scientists are appearing on BBC Radio Oxford every day this week to perform live science experiments.

Andrew Steele, Rosalind West, and Suzie Sheehy - three DPhil students from Oxford University's Department of Physics - will be joining Breakfast Show presenter Malcolm Boyden on BBC Oxford 95.2 FM at 7:15am [or the repeat at 8:15am] every morning.

They'll be performing and explaining different science demonstrations and exploring answers to 'impossible questions': such as how the Universe came into existence and what the future of computing has in store.

In their first slot they showed Malcolm how anyone can find their own retinal blind spots with just a sheet of paper and a pen. They then went on to show how you can see the retinal blood vessels that criss-cross your vision, but that the brain normally 'edits' out, with a pen torch.

If you missed this morning's edition watch what they got up to on this BBC Oxford video or listen again on BBC iPlayer.

UPDATE: Watch a video of Tuesday's experiments here.