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Experience at the Statistical Physics of Complex Systems conference

Posted By Gina Gunaratnam, Friday 24 January 2020
Updated: Thursday 23 January 2020

authors: Davit Aslanyan and Tomohiro Hashizume

The Statistical Physics of Complex Systems Conference was held on May 7-11, 2019 at the Nordic Institute for Theoretical Physics (NORDITA) in Stockholm, Sweden. The event was organized by Statistical and Nonlinear Physics Division of EPS. With the support from EPS Young Minds project, which provided several bursaries for students, Tomohiro Hashizume, a Strathclyde SCOPE representative, and Davit Aslanyan, a Yerevan Young Minds section member, were able to attend this meeting.

As Tomohiro’s background is studying dynamics of strongly correlated quantum systems on an exotic lattice geometry and coupling graphs, he was excited to attend the conference. For him, a talk on statistical physics on complex networks by Prof. Gabrielli and a talk on the thermodynamics and statistical physics on strongly correlated open system were particularly interesting. “They gave me a great insight into the tools and techniques on interpreting the physical processes happening in such exotic systems,” Tomohiro noted.

For Davit, a big highlight of the conference was the power grid symposium. It featured a talk on electric clock lag caused by power grid frequency fluctuations. Presenters also discussed some possible methods aimed at preventing this problem. Another talk highlighted the future European electricity network model fueled mostly by wind and solar energy, and applied statistical physics’ role in calculating how much storage and backup conventional power plants will be needed to sustain the effective work of the system.

It is worth mentioning that the topics of this conference went beyond conventional statistical physics. Many of the talks were on statistical physics’ techniques applied to real-world problems such as optimisation of air travels, neurological systems, social behaviours, and development of fault-safe mechanism for working on a complex networks.

Apart from the technical talks, NORDITA provided us with a nice dinner cruise along the northern coast of Sweden with gorgeous landscapes of Stockholm archipelago with amazing Swedish food.

To conclude with, the conference was saturated with talks on interesting topics, provided venues both for informal and formal discussions, gave an opportunity for young scientists, such as us, to gain experience and get advice from leading researchers of the field and lay the foundations for collaborations. Of course, we were also able to present our researches and promote EPS Young Minds project during the poster session.

We are very thankful to EPS and Young Minds project action committee for giving us an opportunity to participate in this conference. 

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Looking inside 3D silicon nanostructures without leaving a trace: “the Good, the Bad, the Ugly”

Posted By Gina Gunaratnam, Monday 20 January 2020
Updated: Monday 20 January 2020

authors: Diana Grishina, Willem Vos

Scientists from the University of Twente and the European Synchrotron Radiation Facility in France have discovered a new method to non-destructively look inside three-dimen­sional (3D) nanostructures without breaking them. The study is timely since 3D nanostruc­tures are drawing a fast-growing attention for their advanced functionalities in nanopho­tonics, photovoltaics, 3D integrated circuits, and flash memories. The traditional way to look inside 3D nanostructures is to cut them from their substrate, or slice them and view each slice separately. The new method allows to view the complete 3D structure of the whole nanodevice without cutting or breaking. Hence the traceless method allows to use the device further after the 3D image was made. The breakthrough results just appeared in the leading journal ACS Nano of the American Chemical Society (ACS). 

The world around us is truly three-dimensional. As a child you learn that you do not want to break things when checking out your surroundings. The same holds for scientists: once you manage to fabricate a new experimental sample, you do not want to destroy it while investigating whether it indeed behaves as expected. This holds even more so in the wonderful world of nanotechnol­ogy where functional properties of nanostructures are essentially defined by the 3D arrangement of material inside. Therefore, nanotechnologists carefully design 3D nanostructures to achieve a specific functionality. And in real life, new samples never match the initial design perfectly, so it is crucial to investigate what your sample turned out to be.

Figure 1. Electron microscope images of three 3D photonic crystal nanostructures fabricated in the same way. Each external surface looks closely matches the design and looks like the other, but the functionality and internal structure will appear to be completely different.

A simple approach to figure out if your fabricated nanostructure matches the design, is to study it under the microscope. To illustrate the challenges in such an approach let us consider the following quiz: Let us consider three samples shown in Fig. 1 that are fabricated in the same way. Can you tell by the appearance in the electron microscope images, whether they are indeed the same inside and have the same functionality?

Obviously, a microscope image only gives information about the outside of the sample, whereas know-how of the internal structure is needed. Traditionally, this challenge is solved by slicing the sample into thin layers and studying the layers one by one to learn about the internal structure. Such popular, yet destructive methods have an obvious disadvantage: one may find that the sam­ple was made according to specifications, but alas, it is then destroyed. Suitable ways to view inside 3D structures are X-ray methods. But even in recent X-ray work, samples were typically cut out from the device or substrate to achieve sufficient transmission and contrast.

In their new paper, the team demonstrates “traceless X-ray tomography” (TXT). One major step forward is the much greater feasible thickness of the sample of more than a millimeter of silicon, due to the much higher X-ray photon energy. Grishina enthuses: “In modern nanotechnol­ogy this is plenty sufficient to image through wafers. Indeed, all silicon device remained untouched and “as is” during the study.” Moreover, the team’s method greatly improved the total sample size to field-of-view ratio, allowing to zoom-in on the desired region.

Holographic tomography experiments were performed at the European Synchrotron Radiation Facility (ESRF). The hard X-ray beam with 17 keV photon energy propagates in the z-direction and is focused with multilayer coated Kirkpatrick-Baez optics to a tiny, 23 nm x 37 nm, focus. Cloetens explains: “One key feature of our TXT study is the use of X-rays with a much higher photon energy than before. Therefore, the attenuation length for silicon is 640 μm, which is 9 to 20× greater than before, and sufficient to traverse wafer-thick silicon substrates.” The sample is placed at a small distance downstream from the focus and the detector is placed further downstream. ­­At each distance, 1500 images were rec­orded while ro­tating the sample about the Y–axis as shown in Figure 2. The data processing is an intensive two-step procedure consisting of a phase retrieval step followed by a tomographic reconstruction.


Figure 3. Birds-eye view of reconstructed 3D silicon nanostructures shown in the SEM im­ages in Fig. 1. (A) 3D photonic crystal that reveals a broad photonic gap in agreement with theory: “the Good”. (B) 3D photonic crystal that reveals a large void due to stiction resulting from violent liquid evaporation in the pores: “the Bad”. (C) Sample that shows shallow pores due to a fabri­cation error: “the Ugly”. The nicknames are inspired by a fa­mous “spaghetti western”.

The team studied exemplary 3D photonic band gap crystals made from silicon by CMOS-compatible means (a breakthrough a few years ago.) They obtained real space 3D density distributions with 55 nm spatial resolution. TXT identifies why nanostructures that look similar in electron microscopy (see Figure 1) have vastly different nano­photonic functionality: One "Good" crystal with a broad photonic gap reveals 3D periodicity as designed (see Figure 3), a second "Bad" structure without gap reveals a buried void, a third "Ugly" one without gap is shallow due to errors during the fabrication. Vos explains: “TXT serves to non-destruc­tively differentiate between the possible reasons of not finding the designed and expected perfor­mance. This is why we think that TXT is an original and powerful tool to critically assess 3D func­tional nanostructures. Judging from responses at conferences, it seems that our colleagues agree. Or is it perhaps because they like spaghetti-Western movies?

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The EPS Alfvén Prize 2020 is awarded to Dr Annick Pouquet

Posted By Gina Gunaratnam, Monday 13 January 2020
Updated: Monday 13 January 2020

EPS Alfvén Prize 2020

Dr Annick Pouquet

Laboratory for Atmospheric and Space Physics, University of Colorado

and National Center for Atmospheric Research

 Boulder, Colorado, USA

 

Short citation

For fundamental contributions to quantifying energy transfer in magneto-fluid turbulence. Annick Pouquet’s contributions, together with her colleagues, include predicting the inverse cascade of magnetic helicity, extending the accessible frontier of nonlinear numerical computations, and key steps forward in the analytical theory of turbulence. Her work has facilitated remarkable advances in the understanding of turbulence in astrophysical and space plasmas.

Long citation

From the outset of her scientific career, Annick Pouquet has been a pioneer in the field of theoretical and computational turbulence, in both neutral and conducting fluids. Her research has influenced many subfields of plasma physics, spanning laboratory, space and astrophysical plasmas, with applications ranging from solar and planetary interiors to the solar wind and interstellar medium.

Her earliest work on MHD turbulence and dynamo theory placed Annick Pouquet among the leaders of her field. The series of papers produced in this early study, published in the Journal of Fluid Mechanics in the mid-1970s, remain among the most influential works in the field. These publications helped establish the foundations for modern MHD dynamo theory in the nonlinear framework, including: its existence and saturation in a turbulent setting; prediction of an inverse cascade of magnetic helicity; and establishing what is now referred to as the selective decay hypothesis. Her subsequent work in diverse topics related to MHD turbulence and dynamos, such as properties of MHD structure functions, magnetic velocity field correlations, exact scaling laws (the Politano-Pouquet relation), and the non-universality of decaying MHD turbulence, are a testament to her continuous and sustained influence on the field.

Annick Pouquet’s work has been consistently at the forefront of computational physics, applying and adapting new methods and techniques to address important problems in fluid and plasma turbulence. Together with her collaborators, she has performed some of the most sophisticated and detailed simulations of fluid turbulence. She was also an early champion of encouraging open source data. Her knowledge and expertise also served the broader computational physics community in her role as an associate editor for the Journal of Computational Physics for more than twenty years. In addition to her influential work as a researcher, she has played a vital role in advancing the field of plasma physics and in supporting the careers of many young plasma physicists. In her positions as Director of the CNRS Cassini Laboratory in France, as acting Director of the Earth and Sun System Laboratory at NCAR in the USA, and subsequently deputy Director, and as Director of the Geophysical Turbulence Program at NCAR, she has been a powerful advocate for the importance of fundamental research in turbulence, fluid dynamics and plasma physics in general. She has also been a steady proponent of gender equality at all stages of her career.

Annick Pouquet’s enthusiasm for science has impacted all those who have had the privilege to work alongside her. The award to her of the EPS Alfvén Prize 2020 reflects her many, diverse, and important contributions to the advancement of MHD theory.

Tags:  2020  EPS Plasma Physics Division  EPS PPD  Hannes Alfvén Prize  prize 

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Season's greetings

Posted By Administration, Thursday 19 December 2019

The EPS would like to wish all of its members a wonderful holiday season.

The secretariat will be closed between Christmas and New Year.
The EPS secretariat will be closed between 21 December 2019 and 1 January 2020.Click here to contact us.

 

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Every year again: Physical Experiments in Advent

Posted By Gina Gunaratnam, Tuesday 19 November 2019

24 entertaining physics experiments will again be offered this year under the motto "24 more experiments until Christmas" in cooperation with several national and international physical societies and STEM initiatives. Many great prizes can be won.

"PiA - Physik im Advent" is an Advent calendar of a special kind: a physical Advent calendar. Behind every little door there is some education and fun. From 1st to 24th December, small physical experiments that can be carried out with standard household materials will be presented every day as videos by Mr. Santa or Ms. Santa. Participants do the experiments and answer a question on the PiA website. On the following day, there will be a solution video and, if the answer is correct, a point. At Christmas, all participants will receive individual certificates. Among the best participants, prizes will be raffled off in the categories of individual, school class or school, for which numerous donors have donated in cash or kind. In addition to iPods, books, and experimental kits, there will also be a trip to Dallas to watch NBA basketball games with Dirk Nowitzki. Anyone who registers at https://www.physics-in-advent.org can participate. Registration is free and opens on 1st November, PiA starts on 1 December. Posters and flyers can be requested free of charge via the contact form on the PiA website.

„PiA - Physik im Advent" is aimed at children and young people aged between 11 and 18 years, and will take place for the seventh time in 2019. Last year, a new record was set with 40,000 registered participants, 49% of whom were girls, and 1.7 million visitors overall. All parents, teachers, students or adults interested in physical phenomena are invited to participate. "PiA - Physics in Advent" is intended to awaken in all people the joy of experimenting on one's own and offer entertainment and learning at the same time. The calendar is available in German and English.

The project is supported by numerous people from science, television or politics. The patron is the biophysicist and Nobel Prize winner Prof. Dr. Erwin Neher.

This year, for the first time, we also offer PiA news vie the messenger Telegram via the channel „PhysicsInAdvent“.

"PiA - Physik im Advent" is offered in cooperation with the Georg-August-Universität Göttingen, the Wilhelm und Else Heraeus-Stiftung, the Deutsche Physikalische Gesellschaft (DPG), the Österreichische Physikalische Gesellschaft (ÖPG), the Schweizer Physikalische Gesellschaft (SPS), the Netherlands' Physical Society, the European Physical Society (EPS), IUCAA (India), „Global Sphere“, „Science on Stage“, „Komm Mach MINT“ as well as „MINT Zukunft schaffen“. It takes place in cooperation with the successful project "Mathe im Advent" of the German Mathematical Society (DMV).

In order to facilitate the editorial work, the PiA team offers texts, audio and video material on the Internet at http://www.physik-im-advent.de/media Further information is available on the website or on the social media channels:

https://www.physics-in-advent.org
http://www.facebook.com/PhysikImAdvent
https://twitter.com/PhysicsInAdvent

https://www.instagram.com/physikimadvent
https://t.me/PhysicsInAdvent
https://www.physik-im-advent.de
https://twitter.com/PhysikImAdvent

Contact:
Prof. Dr. Arnulf Quadt
Georg-August-University of Göttingen
II Physics Institute
Friedrich-Hund-Platz 1
37077 Goettingen, Germany
aquadt@uni-goettingen.de

By the way, many journalists also enjoy "PiA - Physics in Advent"!

Tags:  DPG  EPS Member Societies  German Physical Sociey  outreach 

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Travel grants to attend ESOF2020 in Trieste

Posted By Gina Gunaratnam, Tuesday 29 October 2019

Travel grants are available from EuroScience for postdocs in any field of physics to attend ESOF2020 from 5-9 July 2020 in Trieste (IT).
More information can be found here: https://www.euroscience.org/calls/travel-grants-to-esof2020-heraeus/.

The deadline to apply is 18 November 2019.

Tags:  2020  conference  ESOF2020  EuroScience 

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eLife on a global research effort: How do you run and share your research?

Posted By Administration, Tuesday 24 September 2019

Do you publish open access, post preprints, make your data readily available? All or none of the above? We’d like to hear from you. We’re asking researchers across the sciences to complete our survey into research practices. It’s our hope that the results will help us and other involved organisations to develop resources and policies in tune with the community needs.

Take the survey now

Tags:  research  survey 

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EPS Historic Sites in Belgium - watch the videos!

Posted By Gina Gunaratnam, Tuesday 20 August 2019

The Belgian Physical Society released videos about two EPS Historic Sites distinguished in Belgium.

On Thursday 23 May 2019, the Heilige-Geestcollege in Leuven, where Georges Lemaître lived and worked when he developed the Big Bang theory, received the prestigious Historic Site Award from the European Physical Society. At the occasion a new bike route dedicated to the Big Bang theory was festively opened. Details about the event can be found here.


On 24 October 2015, the European Physical Society [EPS], the Belgian Physical Society [BPS] and the International Solvay Institutes [ISI] honoured the Hotel Metropole in Brussels as EPS Historic Site.

Tags:  Belgian Pysical Society  Belgium  Big Bang  BPS  EPS Historic Site  EPS National Societies  Metropol  Solvay  video 

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International Day of Light 2019

Posted By Gina Gunaratnam, Monday 13 May 2019

On 18 May 2019, Mulhouse will celebrate the International Day of Light (IDL2019) with a series of workshops for adults and children.
The European Physical Society supports the event.

View the complete programme on the flyer below.

View the IDL2019 events worldwide: https://www.lightday.org/

 Attached Files:
ijl-definitif.pdf (614.81 KB)

Tags:  IDL2019  International Day of Light  IYL2015  Light  Mulhouse  outreach 

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The April 219 issue of e-EPS is out!

Posted By Gina Gunaratnam, Friday 26 April 2019
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