Tag Archives: astroparticle physics

Nobel Laureate Frank Wilczek hosts first workshop on axions as professor at Stockholm University

Stockholm University and NORDITA host this week an international workshop on axions and dark matter. Axions are hypothetical particles proposed by Frank Wilczek who this year started his appointment as professor at Stockholm University.

Dr. Frank Wilczek shared the Nobel Prize in 2004 with David J. Gross and H. David Politzer for discovering the equations that describe the strong force that is responsible for holding atomic nuclei together. With a generous grant from the Swedish Research Council Frank Wilczek has started a joint appointment at Stockholm University and the Massachusetts Institute of Technology (MIT). Throughout his career Frank Wilczek has worked on a number of different problems in condensed matter physics, astrophysics, and particle physics, including proposing new particles.

su_frank-wilczek_500pxAxions are hypothetical particles invented in the late 1970s to solve a major blemish of the standard model of particle physics, namely its failure to explain why the fundamental laws of physics look almost the same if you run time backwards. To address this issue Roberto Peccei and Helen Quinn postulated a new kind of symmetry, now called Peccei-Quinn (PQ) symmetry. Frank Wilczek and Steven Weinberg independently realized a key consequence of PQ symmetry, which its authors had overlooked: it implies the existence of a new particle that Wilczek named the axion, after a laundry detergent (since it removes a stain). If axions exist, they will not only solve a big problem in fundamental physics – they are also likely to supply the mysterious ‘dark matter’ observed by astronomers.

In recent years axions have inspired many new theoretical investigations, recorded in thousands of papers. Importantly, now the stage seems set for breakthroughs on the experimental front. Stockholm University and NORDITA (The Nordic Institute for Theoretical Physics) are hosting an international axion dark matter workshop in Stockholm, December 5-9, bringing together leading researchers in the field. Frank Wilczek is among the organizers of the workshop.

Frank Wilczek comments: “It’s been a joy to see the ideas around axions grow in many directions, from their roots in fundamental physics to cosmology and even, recently, the description of interesting materials.  But I’d love to see axions themselves move from virtual reality to augmented reality.  I’m optimistic that we’ll make that big step soon. The physics world is hungry for it, and we’re mobilizing.’’

More information on Axion Dark Matter workshop in Stockholm, December 5-9

”Augmenting Reality: Axions, Anyons, and Entangled Histories” – Video of Frank Wilczek’s Installation colloquium, November 24

Time for PhD thesis defenses at the Oskar Klein Center

This spring there have been several PhD theses defenses here at the Oskar Klein Center, and as much as we hate saying good bye to some of our best students, we are proud to have been part of their professional lives.
The first to go was Jakob Nordin who defended his thesis with the title “Spectral Properties of Type Ia Supernovae and Implications for Cosmology” the 27th May 2011. During his PhD under the guidance of Professor Ariel Goobar, Jakob collected spectroscopic data of Type Ia supernovae with the purpose to study if SNIa are indeed good “standard candles” over a wide redshift range, a necessary condition to use these explosions to study the properties of dark energy. He has also investigated the nature of one of the color-brightness relation, one of the largest astrophysical corrections in the use of SNIa to measure distances. Finally, he has written a Monte-Carlo simulation package to investigate how systematic uncertainties in the use of Type Ia SNe as distance indicators propagate into our cosmological fits of dark energy parameters. Jakob is now ready to move on with a postdoc at the Berkeley, and we really wish him good luck with his life in California!

Another of Ariel Goobar students, Teresa Riehm also student at the Astronomy department, defended her thesis “Investigating the Dark Universe through Gravitational Lensing”. Continue reading Time for PhD thesis defenses at the Oskar Klein Center

Interview with Zhaoyu


Zhaoyu Yang is one of the OKC postdocs, working at both Fermi and Atlas experiments. It so happens that Zhaoyu also shares the office with me at the Elementary Particle Physics group, on the fourth floor, which is why it came natural to me to start by getting to know her better. With this interview we start a series featuring people working at OKC. Continue reading Interview with Zhaoyu

Welcome to the Oskar Klein Centre blog

As a way to communicate more quickly and efficiently between ourselves in the Oskar Klein Centre (OKC) and with the outside world, we have with the advice of Serena Nobili, responsible for OKC information and outreach, started this blog. Here you will now and then get updates on what is happening in the Centre Continue reading Welcome to the Oskar Klein Centre blog