Sem Sælands vei 24
Gabrijela Zaharijas, University of Nova Gorica
The Isotropic Gamma-ray Background (IGRB) up to 820 GeV has been recently measured by the Fermi LAT using 50 months of data. Understanding the origin of this IGRB is a crucial task that requires to identify and model possible contributions in detail. Dark matter annihilation signals integrated over all cosmic epochs have been proposed to account for a portion of the measured IGRB intensity. I will discuss the theoretical predictions for the clustering of dark matter signal and refined predictions for the contribution of the unresolved astrophysical source populations to the IGRB. We use these ingredients to set the limits on the dark matter annihilation cross section which turn out to be comparable to the ones set by the observation of dwarf spheroidal galaxies and Milky Way halo for sub-TeV dark matter masses, while they improve upon them at the high mass end due to the significant energy extension of the isotropic measurement. In addition I will compare these finding with complementary techniques which probe the cosmological dark matter annihilations, as those of the small scale angular anisotropies and gamma ray cross correlations with galaxy catalogs.
(Slides are now available)
Erik Fooladi (Høgskulen i Volda) will talk about food, gastronomy and sciences.
* Note that the seminar will exceptionnaly be at 14:15! *
David Mota, ITA
Several extensions of the standard cosmological model include scalar fields as new degrees of freedom in the underlying gravitational theory. A particular class of these scalar field theories include screening mechanisms intended to hide the scalar field below observational limits in the solar system, but not on galactic scales, where data still gives freedom to find possible signatures of their presence. I describe how one can use structure formation to study screening mechanisms in extensions to General Relativity. In particular, I will present observable signatures of modified gravity in the nonlinear matter power spectrum, on the halo mass function and other properties of galaxy clusters. Those would help us to discriminate between models with and without scalar fields and even between different screening mechanisms.
(The slides are now available)
Dr. Terry Onsager, National Oceanic and Atmospheric Administration, USA/Space Weather Prediction Center, USA.
David Fonseca Mota from the Institute of Theoretical Astrophysics at UiO will present us his work. He comes for the second time in our group, and he will present us the second part of his talk (see the complete summary under).
Kåre Olaussen, NTNU Trondheim
After 100 years people are still trying to modify (or mutilate) the Einstein General Theory of Relativity. I will first give a general overview of various possibilities, as I learned at a workshop this summer.
Next I will discuss in more detail the possibility of a non-minimal coupling of Einstein gravity to scalar fields, and some modest computations I have done with a master student on that model (in the Robertson-Walker geometry).
The presentation will mainly be aimed at an audience with limited experience with general relativity.
(Slides will be available after the talk).
Ben Rogers, Geology MESci Student at the University of Liverpool, will present his work on "Magma ascent in layered elastic media: insights from field studies and analogue experiments".
Ipsita Mandal, Perimeter institute
We devise a renormalization group analysis for quantum field theories with Fermi surface to study scaling behaviour of non-Fermi liquid states in a controlled approximation. The non-Fermi liquid fixed points are identified from a Fermi surface in (m+1) spatial dimensions, while the co-dimension of Fermi surface is also extended to a generic value. We also study superconducting instability in such systems as a function of dimension and co-dimension of the Fermi surface. The key point in this whole analysis is that unlike in relativistic QFT, the Fermi momentum kF enters as a dimensionful parameter, thus modifying the naive scaling arguments. The effective coupling constants are found to be combinations of the original coupling constants and kF.
The slides are now available.
Endre Joachim Mossige (Mathematic Department, UiO/Trilobite Microsystems, Kristiansand, Norway), will present us some aspects of his PhD work.
Tomás Gonzalo, University College London
Grand Unified Theories are a very well motivated extension of the Standard Model, but the landscape of models and possibilities is overwhelming, and different patterns present rather distinct and unique phenomenology. We present in this work a way to automatise the model building process, by considering a top-bottom approach that constructs viable and sensible theories from a small and controllable set of inputs at the high scale. By providing a GUT scale symmetry group and the field content, all the possible symmetry breaking paths are generated and checked for consistency, ensuring anomaly cancellation and Standard Model embedding. We emphasise the usefulness of this process for various models such as a Supersymmetric SO(10) model, a non-SUSY left-right symmetry model or a theory of GUT inflation.
(Slides are now available).
Oliver Plümper, Assistant Professor at Utrecht University, will present his work on "The nanoscience of geological processes: From fault friction to reactive fluid flow".
The European Space Expo will visit Oslo, Norway from 28 August to 6 September. During the Space Expo we will give three talks on space and ionospheric research. The talks are open for everybody!
Semih Turkaya (Institut de Physique du Globe de Strasbourg, France) will present us his PhD work done with his coauthors Renaud Toussaint, Fredrik Kvalheim Eriksen, Megan Zecevic, Guillaume Daniel, Eirik G. Flekkøy, and Knut Jørgen Måløy.
The conference aims to promote scientific exchange and the development of novel ideas, with a particular emphasis on interdisciplinarity.
Trial lecture title: Anomalous Diffusion: From Condensed Matter and Biological Systems to Financial Markets
Dissertation title: Modelling the onset of frictional sliding: Rupture fronts, slow slip, and time-dependent junction laws
Yong Tang, KIAS
This talk will discuss some possible connections between neutrinos and dark matter, in light of astrophysical observations. Contents include self-interacting dark matter, sterile neutrinos and IceCube Events.
The slides are now available.
Hong-Yan Shih, PhD student at University of Illinois at Urbana-Champaign, willl give a talk on "The emergence of collective modes, ecological collapse and directed percolation at the laminar-turbulence transition in pipe flow".
Kalliopi Petraki, NIKEF Amsterdam [slides]
Observations of the galactic and sub-galactic structure of our universe suggest that a shift from the collisionless cold dark matter paradigm may be needed. Dark matter with sizable self-interactions offers a compelling explanation of these observations.
Particle physics models of self-interacting dark matter can be well accommodated within the asymmetric dark matter scenario. Asymmetric dark matter hypothesizes that the relic dark matter abundance is due to an excess of dark particles over antiparticles, and allows for sizable and direct couplings of dark matter to light force mediators.
In addition, the dark particle-antiparticle asymmetry may be related to the baryon asymmetry of the universe, thus offering a dynamical explanation for the similarity of the dark and the ordinary matter abundances. Exploring the low-energy phenomenology of self-interacting asymmetric dark matter, including the effect on the dynamics of dark matter halos and possible detection strategies, presupposes understanding the cosmology of these models, which can be quite involved. I will discuss the above, and illustrate them in the context of the atomic dark matter model.
On June 18th and 19th, the “kick-off” seminar for the Strategic Research Intitiative EarthFlows will be arranged in Oslo.
Talk by François Renard (ISTerre, Univ. Grenoble Alpes & PGP, UiO) in relation with the EarthFlow project, but addressed to a broad audience.
Thema 1 of the EarthFlow project will be presented by Olivier Galland (PGP, UiO), Atle Jensen (Department of Mathematics, UiO) and Martin Dabrowski (PGP, UiO).
Kai Schmidt Hoberg, DESY, Hamburg [slides]
I will review motivations for the existence of self interacting dark matter and discuss possible astrophysical observables. Self-interactions of dark matter particles can potentially lead to an observable separation between the dark matter halo and the stars of a galaxy moving through a region of large dark matter density. Such a separation has recently been observed in a galaxy falling into the core of the galaxy cluster Abell 3827. I discuss the DM self-interaction cross section needed to reproduce the observed effects.
Are you also curious to know what research is brewing on the other side of the hall in PGP-AMKS group? We are launching a new Friday seminar event, the Poster Friday, with the first time coming Friday. Please join us, where we kick off this first session with posters involving flow in porous media, microfluidics, visco-elasticity and many things more!
The research centre for dark matter, The Strategic Dark Matter Initiative - SDI, will officially be launched on Friday, and invites you all to a popular science lecture, with coffee and snacks.