Tutkijoiden yö 2020

Koronavirus tilanteesta johtuen vuoden 2020 Tutkijoiden yö järjestettiin etäyhteyksien avulla. Tutkijoiden yö on eurooppalainen tiedetapahtuma, jonka ideana on avata tutkimusta ja sen tekemistä yleisölle. Lisää aiheesta voit lukea Tutkijoiden yön virallisilta nettisivuilta.

Myös HIP (Fysiikan tutkimuslaitos tai Helsinki Institute of Physics englanniksi) oli mukana tapahtumassa, koko ohjelman löydät täältä. Myös meitä teoreetikoita pyydettiin mukaan ja niin syntyi video nimeltä Gravitaatioaaltoja ja kuplia. Siinä käyn läpi hiukan meidän ryhmämme yhtä tutkimuksen kohdetta, ensimmäisen kertaluokan faasitransitiossa mahdollisesti syntyviä kuplia. Video alkaa kertauksella siitä, miten maailmankaikkeus on syntynyt ja mikä se hiukkasfysiikan standardimalli nyt oikein onkaan. Lisäksi käymme nopeasti läpi myös gravitaatioaaltoja.


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Summer students 2020

This summer (nor the year) didn’t go quite as planned. Due to the work from home recommendation, the office was replaced by a kitchen table and coffee breaks turned into virtual ones. The CFT group had hired five summer students and here are their thoughts about their projects.

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Saunas and Sea Ice: Studying in Suomi and Sussex

Visiting graduate student Daniel Cutting was back in Helsinki for a week and in that time attended the Fall Meeting and Christmas Dinner of our Doctoral Programme in Particle Physics and Universe Sciences. He was invited to give a presentation but, rather than speaking about his research–which includes one paper based partially on work done in Helsinki with Helsinki researchers–Daniel gave a rather different kind of talk. Here is what he has to say:

This year I had the opportunity to visit Helsinki University for a series of months to continue my studies as a PhD student in Theoretical Particle Physics. While I am usually based at the University of Sussex in the United Kingdom, I quickly warmed to the atmosphere and culture at the University of Helsinki and greatly enjoyed my time here. My latest visit to Finland happened to overlap with the PAPU Christmas meeting, and I was asked to give a short presentation on some of the differences I had noticed between studying in Helsinki and Sussex as a PhD student.

One of the more substantial differences I noted is the culture relating to PhD students – and whether they are treated more like employees or students. In the UK we lean towards the latter, whereas here in Finland it seems like the former is more applicable. Another big change is that in the UK it is common to have set time limits on how long our PhD’s can take to complete – in my case I have a hard cut off after 4 years of study before which I must have submitted my thesis. On the other hand there is no minimum number of papers required to submit your thesis.

The meeting itself was a fun event with many fascinating presentations from current and recently graduated students on their research projects. Learning more about what everyone does within PAPU was a great way to spend the day.

I’ve enjoyed my time at both Sussex and Helsinki, and I am sure this won’t be my last visit to Finland!

Read about Daniel’s experiences at the LISA Cosmology Working Group workshop here.

VR visualisation with Blender

Blender render time spender.

I was playing around with VisIt last summer as a part of my job. Someone then asked me if I can do 360 videos with the data. I answered no at the time. Fast-forward to the present. Turns out that yes, you indeed can do 360 VR visualisations with your scientific data. Neat, isn’t it? Well, at least I thought so and decided to give it a try. And well, here we are.

This is a tutorial of sorts about all the stuff I’ve learned. I’m assuming that the reader is completely new to Blender and maybe even a bit intimidated by it, like the author was. Hence for those Blender experts out there, this tutorial is very hand holdy.

The visualisation I’ve been working on is this VR animation of cosmic necklace network that consists of cosmic strings (green) and magnetic monopoles (red). More information on the system can be found from the video description as well as links to the scientific papers the simulation is based on. Now you can experience the possible events of early universe in VR!

I feel like I should state that doing VR visualisations is not very hard, it just
takes infuriatingly long to actually get it working. Here are eight easy steps how to do that.

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What happened at the LISA Cosmology Working Group workshop

The LISA Cosmology Working Group Workshop dinner at Särkänlinna restaurant.

Credit: Anna Kormu

Visiting graduate student Daniel Cutting has written a short summary of what happened at last week’s LISA Cosmology Working Group Workshop in Helsinki. Here is what he has to say:

During the last week, the Helsinki Institute of Physics hosted the 5th LISA Cosmology Working group meeting. This group has been formed to develop and inform on the cosmological science that can be conducted with the upcoming space-based gravitational wave detector called LISA.

The LISA mission will be formed of three satellites in an equilateral triangle separated by millions of kilometres following the Earth in an orbit around the Sun. The detector will be sensitive to a large range of sources, ranging from mergers of supermassive black holes in galactic centres to exotic objects such as cosmic strings formed in the early universe.

The meeting began with an update on the current status of the development of the LISA consortium. This is the organising body responsible for developing the technology and science for the LISA mission. In particular, we learnt more about the work packages that the Cosmology Working Group needs to carry out in order for the LISA mission to deliver the science it has promised.

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Group members talk in Tampere

View of Tammerkoski in Tampere

Particle cosmologists and astrophysicists from the Universities of Helsinki and Jyväskylä held a joint meeting in Tampere last week. The early spring weather was lovely and the standard of all the talks was very high.

Masters student Lauri Niemi told us about his work on simulating extensions of the Standard Model with non-perturbative methods. Sometimes existing results can be re-used, but in many cases new simulations are required. Part of his PhD studies will involve carrying out those simulations.

Daniel Cutting, visiting us from Sussex, gave a talk about his simulations of vacuum scalar bubbles and the resulting gravitational wave power spectrum. His movies and other visualisations went down very well with the audience.

Sara Tähtinen spoke about gravitational waves from a tachyonic transition, in scenarios where non-Abelian gauge fields play a role. Because non-Abelian gauge fields self-interact strongly, the results are rather different from previous studies of gravitational waves from tachyonic preheating.

Image credit: Jorge Franganillo (CC BY 3.0) [source].

A visitor from Odense

PhD student Arianna Toniato has been visiting us for the past month from CP3-Origins, a research institute at the University of Southern Denmark in Odense. As part of her PhD programme, she has to spend some time at a foreign university, and she chose to come to Helsinki. Arianna has been working with Kari Rummukainen and Kimmo Tuominen on lattice simulations of composite Higgs models.

Arianna says that she has enjoyed “pretty much everything about being here, the university, the people at the university, the city, and the frozen sea”. Today is her last day visiting our group.

In the autumn Arianna will start as a postdoc with Harvey Meyer in the Theory Group at the Johannes Gutenberg University Mainz. We wish her all the best in her future career!

Summer jobs in computational field theory and gravitational waves

Log-scaled kinetic energy for a simulation of a first-order phase transition in a field-fluid model.

We are looking for 1-2 summer trainees with a background in theoretical physics and preferably with good programming skills. The positions are for three months, with exact dates to be agreed upon.

We study theories of particle physics using large-scale numerical simulations, usually applied to cosmology. In particular, our research topics include gravitational wave production in the early Universe, phase transitions in beyond the Standard Model theories, and algorithmic development. The trainees’ research projects are chosen according to the experience and preference of the trainees. The research projects can form the basis for either a Bachelor or a Master thesis.

Read the official advertisement here and apply with this form. The deadline is 6.2.2018.