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Africa calling: stars, sky and the greater good

3 May 2017

If you think about the skills required for the social and economic progress needed by developing countries, radio astronomy is probably not very high on your list. However, the assumptions one makes about applied technical sciences and their worth to such nations might be unwarranted if a new research project is anything to go by.

Development in Africa with Radio Astronomy (Dara) aims to train a new, and in many cases a first, cohort of radio astronomers in sub-Saharan African countries. The University of Leeds-led project began as a Royal Society grant belonging to Melvin Hoare, Professor of Astrophysics.

Professor Hoare did some initial radio astronomy training in Ghana via the funding, before gaining a substantial grant in 2015 from the Newton Fund – which is part of the UK’s overseas aid commitments, and is delivered through the Science and Technology Facilities Council. With that grant, Dara trained scientists in Zambia, Kenya, Namibia and Botswana. Now, thanks to a further £2.7 million injection from the fund, it is being rolled out in Ghana, Madagascar, Mozambique and Mauritius.

Read more about Dara on the Times Higher Education website.




Art Invasion: a painting exhibition by Costas Evangelatos

7 April 2017

The School of Physics and Astronomy were delighted to hold an art exhibition by the artist Costas Evangelatos from Athens, Greece. The paintings were inspired by posters and presentations from the 18th Symposium on Topological Quantum Information that took place in Athens, May 2015.

Read more about the exhibition here




Stretching and squeezing the Haldane pseudopotentials

7 April 2017

Dr Zlatko Papic and collaborators have recently had a paper published in Physical Review Letter, which was highlighted as Editors’ Suggestion. This short article explains the background to the team’s work and the team’s findings.

 

Stretching and squeezing the Haldane pseudopotentials: a new language for describing the anisotropic fractional quantum Hall effect

In a classic paper from 1983 [1], Duncan Haldane (Nobel Prize in Physics, 2016) formulated what is now known as "the Haldane pseudopotentials" to describe the fractional quantum Hall effect. The latter phenomenon, where the Hall conductance of a two-dimensional electron gas in a magnetic field is curiously quantised in terms of rational numbers like 1/3 or 2/5, had been discovered a year earlier by Tsui, Stormer and Gossard [2]. The effect, however, remained a mystery until the early 1983 when Robert Laughlin explained it as a consequence of subtle correlations between the electrons which make them form exotic kinds of quantum fluids. (Tsui, Stormer and Laughlin shared the 1998 Nobel Prize for their discovery.) One of the crucial steps in the verification and ultimate acceptance of Laughlin's theory came from Haldane’s pseudopotentials, which allowed to write down a rotationally-invariant wave function for the Laughlin fluid and explained why such a state could describe the real system of electrons interacting via Coulomb force.

An underlying assumption of the Haldane pseudopotentials has been that the electron system is rotationally invariant – it looks the same in x and y directions. However, it is known that experimental semiconductor systems, which realise the quantum Hall effect, are not rotationally invariant: for example, semiconductors often have different effective masses along x- and y-directions. A natural question then arises: can Haldane pseudopotentials be defined for quantum Hall systems which are not invariant under x-y rotation?

In a recent paper published in Physical Review Letter and highlighted as Editors’ Suggestion [4], Dr Zlatko Papic and collaborators have generalised the 1983 work of Haldane by formulating the pseudopotentials for anisotropic fractional quantum Hall systems. Their work introduces a new and universal language that allows to describe a broad class of fractional quantum Hall systems without rotational symmetry, such as experiments in tilted magnetic field, or the so-called nematic quantum Hall states which spontaneously break rotational symmetry, similar to liquid crystals. The new language also illuminates a fundamental characteristic of fractional quantum Hall fluids – their geometric degree of freedom. Such degrees of freedom determine the properties of these fluids at low energies and have recently attracted much attention because of connections with models of quantum gravity in two dimensions.

Read the paper in full in Physical Review Letters

References

[1] F. D. M. Haldane, Phys. Rev. Lett. 51, 605 (1983).

[2] D. C. Tsui, H. L. Stormer, and A. C. Gossard, Phys. Rev. Lett. 48, 1559 (1982).

[3] R. B. Laughlin, Phys. Rev. Lett. 50, 1395 (1983).

[4] Bo Yang, Zi-Xiang Hu, Ching-hua Lee, and Z. Papic, Phys. Rev. Lett. 118, 146403 (2017).




Inaugural Professor Ian Ward lecture

3 April 2017

The inaugural Professor Ian Ward lecture, hosted by the Soft Matter Physics Group at Leeds, was held in honour of the outstanding contribution of Professor Ian Ward F.R.S to the group, to the University as a whole, and more widely to the National and International Polymer Physics community.

The picture to the right shows a number of the happy band who attended this annual lecture.

The inaugural speaker was Professor Phil Coates (fourth from the right), Professor of Polymer Engineering at the University of Bradford and the Director of the internationally recognised Polymer Interdisciplinary Research Centre (IRC) (across the Universities of Leeds, Bradford, Durham and Sheffield).

Professor Coates has had a long standing association and collaboration with Professor Ward (who was the first director of the IRC on its inception in 1989), stretching back over 40 years. Professor Coates and his team are leaders in the area of the structure and properties of solid polymers and polymer composites, combining fundamental scientific research with strong industrial links, a theme which was pioneered by Professor Ward.

It was great event, allowing for wonderful reflections of Ian’s contribution from both Professor Coates and our head of School Professor Helen Gleeson (back left). Phil gave a very interesting talk, building up from Ian’s pioneering work and highlighting the new areas that Bradford have taken this forward. Phil also highlighted some of Ian’s inventions, including the single polymer composites work currently exploited by Samsonite in their successful innovative luggage range (Cosmolite etc). The event proved a great opportunity for catching up with friends and colleagues across the sites of the IRC. Thanks to Glenys Bowles (second right) and Ella Gould (off stage right) for help in organising the event and we understand that both Ian, and his wife Margaret (fifth from the right) had a lovely evening. Thanks again to Phil for agreeing to gives this inaugural lecture.




Leeds PhD student strikes Bronze for physics display in Parliament

16 March 2017

Ellen Kendrick, a PhD student here at the University of Leeds, struck Bronze at a competition in the House of Commons for the excellence of her physics research, walking away with a £1,000 prize.

Ellen presented her physics research to dozens of politicians and a panel of expert judges, as part of the poster competition STEM for BRITAIN, on Monday 13 March.

Her research, which focuses on using atomic force microscopy to pull apart protein molecules to investigate their strength and flexibility at a range of temperatures, was judged against 29 other shortlisted researchers' work and she came out as one of the three winners.

Ellen said, 'I am very happy and very surprised. I was not just seeing it as a nice day out but it has been fun and I have spoken to representatives of both my MPs [from her home city Edinburgh and her work in Leeds].'

STEM for BRITAIN aims to help politicians understand more about the UK's thriving science and engineering base and rewards some of the strongest scientific and engineering research being undertaken in the UK.

Stephen Metcalfe MP, Chair of the Parliamentary & Scientific Committee, sponsors of the physics awards said: 'The Parliamentary & Scientific Committee is delighted to sponsor the physics awards. This annual competition is an important date in the parliamentary calendar because it gives MPs an opportunity to speak to a wide range of the country's best young researchers.

'These early career engineers, mathematicians and scientists are the architects of our future and STEM for BRITAIN is politicians' best opportunity to meet them and understand their work.'

Professor Roy Sambles, President of the Institute of Physics said:
'STEM for BRITAIN provides a great opportunity for some of our outstanding young scientists to present aspects of their research in parliament, allowing Members of Parliament to find out first-hand about some of the ground breaking research taking place here in the UK.'

'I wish the best of luck to all the exhibitors, who should feel very pleased with what they have achieved and I hope that they will value sharing the excitement of their research with key politicians and policy makers.'

The Parliamentary and Scientific Committee runs the event in collaboration with the Council for the Mathematical Sciences, the Institute of Physics, The Physiological Society, the Royal Academy of Engineering, the Royal Society of Biology and the Royal Society of Chemistry; with financial support from Research Councils UK, Warwick Manufacturing Group, the Clay Mathematics Institute, the Heilbronn Institute for Mathematical Research, the Institute of Biomedical Science and the Society of Chemical Industry.




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