17th September 2021 at 14:15: Minna Palmroth

Our first online Physics Colloquium for this autumn season will take place on Friday, September 17th. Our speaker will be Minna Palmroth, who will talk to us about the recent discovery of a new auroral form, enabled by citizen scientists.

Minna is Professor in Computational Space Physics at University of Helsinki and the Director of the Finnish Centre of Excellence in Research of Sustainable Space. Her research work combines magnetospheric physics and high-performance computing, as she is leading the development of one of the largest supercomputer space physics models.  In 2018, she published a popular science book about the aurora, Revontulibongari opas, which features pictures from aurora hunters all across Finland. This book was the first step to an unexpected scientific collaboration.

In her colloquium, titled Citizen scientists discover a new auroral form: Dunes provide insight into the upper atmosphere, Minna will talk about the journey leading to this discovery and the scientific implications of the citizen scientists’ findings.

The event will be held on Friday 17.09.21 at 14:15, on Zoom (Meeting ID: 679 5239 0566 – Passcode: 036512).

Here is her abstract:

Auroral forms are like fingerprints linking optical features to physical phenomena in the near-Earth space. While discovering new forms is rare, recently scientists reported of citizens’ observations of STEVE, a pinkish optical manifestation of subauroral ionospheric drifts that were not thought to be visible to the naked eye. This talk tells an exciting story of a citizen science project that led to the discovery of a new auroral phenomenon. Dunes are a horizontal stripes in the green aurora, and are currently thought to originate from the oscillation of the underlying atmospheric density. On Oct 7, 2018, citizen observers took multiple digital photographs of the same dunes simultaneously from different locations in Finland and Sweden. We develop a triangulation method to analyse the photographs, and conclude that the dunes are a monochromatic wave field with a wavelength of about 45 km within a thin layer at 100 km altitude. Supporting data suggest that the dunes manifest atmospheric waves, possibly mesospheric bores, which are rarely detected, and have not previously been observed via diffuse aurora, nor at auroral latitudes and altitudes. The dunes present a new opportunity to investigate the coupling of the lower/middle atmosphere to the thermosphere and ionosphere. We conclude that the the dunes may provide new insights into the structure of the mesopause as a response to driving by ionospheric energy deposition via Joule heating and electron precipitation. Further, our paper adds to the growing body of work that illustrates the value of citizen scientist images in carrying out quantitative analysis of optical phenomena, especially at small scales at subauroral latitudes. The dune project presents means to create general interest towards physics, emphasising that citizens can take part in scientific work by helping to uncover new phenomena.

7th May 2021 at 14.15: Emilia Kilpua

Our last online Physics Colloquium for this spring season will take place on Friday, May 7th. We will have an inaugural lecture to be given by Emilia Kilpua, who recently got promoted as Full Professor in our department.

Emilia is an expert in solar-terrestrial physics, and her work focuses on solar eruptions and their impact on near-Earth space. She obtained an ERC Consolidator Grant in 2016 to develop novel simulations to better understand these processes, and is currently also the coordinator of a Marie Sklodowska – Curie Action Innovative Training Network on space weather. She is actively involved in multiple space missions, such as NASA’s Parker Solar Probe and ESA’s Bepi-Colombo and Solar Orbiter.

In her colloquium, titled The Art of Predicting Space Weather, Emilia will talk about the challenges of forecasting the conditions in space around our planet and in our solar system.

The event will be held on Friday 7.05.21 at 14:15, on Zoom (Meeting ID: 614 1662 5342 – Passcode:  844713).

Here is her abstract:

Like normal weather, space weather can be calm or stormy. During big storms near-Earth space experiences dramatic changes; the magnetosphere surrounding our planet gets compressed, electric currents in the magnetosphere and ionosphere intensify and fluxes of high energy particle can rapidly increase by several orders of magnitudes. Vulnerability of modern society to space weather has made forecasting it increasingly important. The quality of predictions is however still very modest. This talk presents the key factors why forecasting space weather is so challenging, and discusses the recent and future steps in the scientific understanding of solar eruptions that are most crucial for improving the predictability.

9th April 2021 at 14:15: Karl Ziemelis

Our next Physics Colloquium for the spring 2021 will take place on Friday, April 9th. We will have a presentation to be given by the current Physical Sciences Editor of Nature, Karl Ziemelis.

Karl Ziemelis received his bachelor’s in Natural Sciences (specializing in physics) from the University of Cambridge in 1988, followed by four years of original research on the optoelectronic properties of conjugated polymers under the supervision of Professor Richard Friend (Cavendish Laboratory, Cambridge), before joining the staff of Nature in 1992, of which he became the Physical Science Editor in 1997.  When time permits, he occasionally writes in a freelance capacity for Nature (having contributed to the news and “News and Views” sections of the journal) and also for the popular science weekly magazine New Scientist.

In his colloquium, titled Writing for Impact, Karl will talk about what makes a great paper and give us some tricks on writing for high-impact journals.

The event will be held on Friday 09.04.21 at 14:15, on Zoom (Meeting ID: 611 3772 2482 – Passcode: 556533 ).

Here is the abstract:

What makes a great paper? Great science, of course! But that is only part of the equation. A great paper will not usually write itself: as the author of such a piece, you need to know your audience, be mindful of your readers’ time and – perhaps most importantly – lay clear foundations for future developments. I will give a Nature editor’s perspective of what works (and what doesn’t), along with some general “tricks of the trade” for maximising the impact of your written work. At the end of the day, you want your papers to be read, used and (maybe) even enjoyed.

5th March 2021 at 14:15: Manohar Kumar

Our second Physics Colloquium for this spring will take place on Friday, March 5th. We will have a presentation to be given by Manohar Kumar, whose recent work in the field of quantum physics was featured on the front cover of Science. In this colloquium, titled Mystery particle anyons finally revealed their identity in a particle collider, Manohar will talk about the discovery of the nature of anyons.

Manohar Kumar obtained his PhD from Leiden University in 2012, and is currently a Research Fellow in the Department of Applied Physics at Aalto University. His research interests include quantum transport, quantum devices and technologies and electron quantum optics, and his current work focuses on graphene.

The event will be held on Friday 05.03.21 at 14:15, on Zoom (Meeting ID:  637 7087 6002 – Passcode: 753457).

Here is the abstract:

Two-dimensional systems at low temperatures and the high magnetic field can host exotic particles with elementary excitations carrying fractional charge e* = e/q such as in fractional quantum Hall effect. These exotic particles are anyonic particles, whose quantum statistics are neither bosonic nor fermionic; instead, they are predicted to obey fractional statistics. The fractional charge of these anyons has been studied successfully using low frequency shot noise measurement. However, a clear sign of the fractional statistics remains elusive. We probed the fractional statistics and the fractional charge of anyons in mesoscopic anyonic collider. Here we collided two independent anyonic excitations at a beam splitter and measured the correlation in the noise fluctuations of outgoing beam currents. Our collision results explicitly extract the quantum phase of Φ = π/3 for the exchange of two anyonic quasiparticles with q = e/3. This is the very first smoking gun result on fractional statistics of anyon. This collider geometry could be extended to perform the ultimate braiding experiment to the realized full potential of a special kind of anyon called non-Abelian anyons in topological quantum computation.

19th February 2021 at 14:15: Otso Ovaskainen

Our first Physics Colloquium for 2021 will take place on Friday, February 19th. We will have a presentation to be given by Otso Ovaskainen, a renowned expert in ecological modelling.

Otso Ovaskainen is Professor of mathematical and statistical ecology at the University of Jyväskylä, starting from the beginning of this year. He has previously worked at the University of Helsinki since 2009. He is the leader of the LIFEPLAN project, funded by an ERC Synergy grant, which aims at mapping global biodiversity, and was granted an Academy Professor position in 2021. His work focuses on ecological research, using mathematical and statistical methods to better understand the dynamics of ecosystem.

In his colloquium, titled A planetary inventory of life – a new synthesis built on big data combined with novel statistical methods, Otso will talk about his current projects using big data and mathematical methods to better understand biodiversity.

The event will be held on Friday 19.02.21 at 14:15, on Zoom (Meeting ID: 616 8515 5291 – Passcode: 338747).

Here is his abstract:

Traditional methods of detecting species are being increasingly replaced by semi-automated methods based on DNA barcoding, camera-traps, bioacoustic monitoring, and other such methods. This has created unprecedented potential for advancing our understanding of nature, but at the same time provides major challenges for data processing and interpretation for two reasons. First, there is the need for converting the information collected by automated samplers to the basic currency of biodiversity analysis: species-level occurrence and/or abundance. Second, current statistical techniques are inherently unsuitable for application to massive scales, both in terms of their underlying assumptions and in terms of their computational performance. I present pilot results of the ERC-synergy project LIFEPLAN (2020-2026) that samples biodiversity at spatial scales covering six orders of magnitude (from 100 m to the global scale of 10000 km) and develops new bioinformatic, statistical and mathematical methods for big ecological data. I show that sampling fungal DNA from the air, arthropod DNA with Malaise traps, birds with autonomous recorders, and mammals with camera-traps provides a highly cost-efficient method for large-scale biodiversity surveys. The pilot results reveal previously undiscovered spatial and temporal patterns in the distribution of global biodiversity, both for its previously known and unknown components.