Events - Page 15

Time and place: May 20, 2016 10:15 AM4:00 PM, Lille fysiske auditorium, Fysikkbygningen

Trial lecture: Pattern formation in granular materials (10:15)

Dissertation: Statistical properties of sheared suspensions (13:15)

Time and place: May 18, 2016 1:05 PM2:00 PM, Ø467

Håvard Tveit Ihle, ITA

There is a growing interest in how the particle nature of dark matter (DM) can affect cosmological and astrophysical observables. Kinetic decoupling of DM from the heat bath in the early universe, e.g., leads to a pronounced cutoff in the matter power spectrum. Traditional WIMP models for DM (like SUSY) typically result in MeV-scale kinetic decoupling, corresponding to a cutoff at unobservably small scales. Here, we provide instead a classification of DM models that result in keV-scale kinetic decoupling. Such models result in a potentially observable cutoff in the power spectrum, at the scale of dwarf-galaxies and hence possibly addressing the missing satellite problem. The main focus of the talk will be on the decoupling process of DM in the early universe, implications for model building, and some examples from our work.

(The slides are now available)

Time and place: May 11, 2016 3:30 PM4:30 PM, Ø467

Robert Wagner, University of Stockholm

The past decade has seen a dramatic improvement in the quality of data available at high-energy gamma-rays. The all-sky LAT instrument on board of the Fermi satellite has revealed about 2,000 sources in the sky at the 100 MeV – 100 GeV band, and almost 200 sources have been detected at even higher energies, E>100 GeV, gamma rays energies by pointed, ground-based Imaging Air Cherenkov Telescopes. 

These so-called very high-energy (VHE) gamma rays gamma rays cannot be produced in thermal processes, but are produced by interactions of high-energy particles. Gamma rays thus trace populations of such particles and enable the cosmic particle accelerators to be imaged and studied. Gamma-ray emitting particle accelerators are ubiquitous in the Galaxy and beyond; they include a variety of galactic and extragalactic objects. Details of the acceleration mechanisms as well as the role high-energy particles play in the evolution of star forming systems and galaxies remain to be fully understood. Gamma-rays can also be used as probes of the physics of the early universe, of fundamental physics, and could be products of dark matter annihilation in some cold dark matter realizations.  

... (continued below)  

(The slides will be available after the talk)

Time and place: May 4, 2016 1:15 PM, Ø467

Bjørn Solheim, FI

What do space and time look like on the very smallest scales ?  Do space and time really exist, or are they just emergent concepts that serve as useful approximations in some physical domains? Following Einstein's insights we are lead to believe that the answers to questions about microscopic geometry lie in finding a microscopic theory of gravity. Loop quantum gravity (LQG) is  a theory that encapsulates the core principles of quantum theory and general relativity (GR) with minimal extra assumptions. LQG can be seen both as a specific quantization of GR, and as a set of general methods for non-perturbative  quantization of diffeomorphism invariant theories in a background independent manner. LQG leads to a well-defined theory of (spatial) quantum geometry, where geometric variables like area and volume take discrete values. LQG has been "successfully" applied to cosmology and black holes where it eliminates the singularities and gives a fully quantum version of these gravitational systems. The presentation will focus on the foundations of LQG with some applications in cosmology.

(The slides are now available)

Time and place: Apr. 29, 2016 3:15 PM, Seminar Room V414

by Vera Schlindwein (Alfred Wegner Institute, Bremen).

Time and place: Apr. 27, 2016 1:05 PM2:00 PM, Ø467

Felix Kahlhoefer, DESY (Hamburg)

I will discuss the motivation, the advantages and the problems of using simplified models as a tool to interpret LHC searches for dark matter. I will present a few examples for how this approach can be used to understand the complementarity of different dark matter search strategies. Finally, I will focus on various consistency conditions that should be imposed even on the most simplified models. These conditions can imply the presence of additional new particles and interactions that may change the phenomenology of the model in important ways.

(The slides are now available)

Time and place: Apr. 15, 2016 3:15 PM, Seminar Room V414

by Harald Throne-Holst from National Institute for Consumer Research (SIFO).

Time and place: Apr. 13, 2016 1:05 PM, Ø467

Anders Tranberg, University of Stavanger

The asymmetry between matter and antimatter is still an unsolved mystery of astroparticle physics. Presumably, the asymmetry was generated during a strong phase transition at or before the electroweak symmetry breaking transition in the Early Universe. Electroweak baryogenesis as a scenario has a long and illustrious history of trial and not-quite-success. I will present a related, competing model ("Cold" electroweak baryogenesis), and demonstrate how one may numerically compute and actual number for the generated asymmetry from first principles.

(The slides are now available)

Time and place: Apr. 1, 2016 3:15 PM, Seminar Room V414

Sebastian Westermann from the Department of Geosciences (UiO) will talk about:

Permafrost in a Changing Climate

Time and place: Apr. 1, 2016 10:15 AM4:00 PM, Lille fysiske auditorium, Fysikkbygningen

Trial lecture: Electromagnetic methods for monitoring of CO2 sequestration (10:15)

Dissertation: Advances in 3D finite-difference modelling of electromagnetic fields in the conductive Earth (13:15)

Time and place: Mar. 30, 2016 1:05 PM, Ø467

Parampreet Walia, FI

Advancements in experiments for unveiling the nature of Dark Matter (DM) call for more accurate predictions from theorists. Thus a lot of recent interest has developed in calculating higher order corrections to DM annihilation and scattering processes.

Typical Majorana WIMP annihilation to fermions is helicity suppressed. But emission of an extra gauge boson can lift this suppression. Electroweak bremsstrahlung has been studied in much detail earlier, but surprisingly not equal attention has been given to gluon bremsstrahlung.

The major difference between the two cases comes from the fact that quarks and gluons fragment to form hadrons.  Computing the spectrum from model to model basis is computationally expensive. I will present a computation friendly approach, which agrees with the real spectrum to a very high accuracy. And then in the end, I would also discuss the impact of QCD corrections on relic density calculations.

(The slides are now available)

Time and place: Mar. 16, 2016 1:05 PMMar. 17, 2016 2:00 PM, Ø467

Riccardo Catena, Chalmers (Göteborg)

About five-sixths of all matter in the Universe remain hidden from our view and behave like a dissipation-less fluid called dark matter. The experimental technique known as direct detection (DD) will play a pivotal role in shedding light on the nature of dark matter during the next decade. It searches for nuclear recoil events induced by the non-relativistic scattering of Milky Way dark matter particles in low-background detectors. An effective theory approach is a solid strategy to interpret DD experiments when the momentum transferred in the dark matter scattering by nuclei is small compared to the mass of the particle mediating the interaction. In this talk I compare a recently developed non-relativistic effective theory for dark matter-nucleon interactions to current DD data, including the observation of a modulation signal in the nuclear recoil energy spectrum reported by the DAMA collaboration. Emphasis will be placed on the strength of the proposed effective theory approach and on how it compares to the standard paradigm for DD.

(The slides are now available)

Time and place: Mar. 11, 2016 3:15 PM, Seminar Room V414

Adam Robertson from the Oslo University Hospital will be delivering a talk about: 

Molecular Effects of the 5-hydroxymethylcytosine DNA Modification

Co-authors: Julia Robertson, Dorota Kororska, Anika Reifschneider, and Adam Robertson

Time and place: Mar. 11, 2016 12:15 PM1:00 PM, Aud I, Dept of Geoscience

Andreas Kääb (UiO, Geosciences) will give a presentation in the framework of the Earth flow project. Note the location and time: in the Geoscience building, probably Aud I, at lunch time, 12:15.

 

Time and place: Mar. 4, 2016 3:15 PM4:00 PM, Seminar room (FV 414)

Audun Skaugen (PhD student, UiO, Condensed Matter Physics) will present his work...

Time and place: Mar. 2, 2016 1:05 PM, Ø467

Abram Michael Beauregard Krislock, FI

Go effectively models physics itself: The game has an enormous amount of complexity and is full of beautiful and mind-boggling phenomena. In spite of this, there are only a small number of rules to the game. A study of go can help one with pattern recognition, logical determinism, strategic planning, and concentration. As physicists are becoming more and more proficient in using sophisticated statistics and computer science for their studies, they may be inspired by an ultra recent advancement in computer learning: For the first time, a computer has beaten a professional player in go. Last but not least, go is a ton of fun.

(Slides will be available after the talk)

Time and place: Feb. 26, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Steffi Burchardt (Associate Professor, Uppsala University) will give a talk about laccoliths:

Laccoliths are magmatic intrusions with an upward-curved roof and two end-member geometries: the so-called Christmas tree and the punched laccolith. In my talk, I will give an overview of laccolith emplacement with examples from the Henry Mountains, Utah, and Elba Island, Italy, before reporting on field work and first results of ongoing research on laccolith emplacement in the cougar-rich Chachahuén volcano. This research is part of the DIPS and MIMES projects.

Time and place: Feb. 12, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Johan Storm (Institute of basic medical sciences, UiO) will talk about the work he does in the "brain signaling" group. His group is interested in signaling and information processing in the brain at multiple levels, from synapses, neurons and circuits, to control of behavior and mental processes, in particular consciousness and memory.

Some citations:

“Understanding consciousness has become the ultimate intellectual challenge of this new millennium”   S. Dehaene  & J.P. Changeux, 2004

“Consciousness is the major unsolved problem   in biology”  Francis Crick, 2004.

Time and place: Feb. 3, 2016 1:05 PM, Ø467

Ivica Picek, university of Zagreb

Besides being a first indication for the second scalar particle, a recent hint for the 750 GeV resonance at the LHC  requires additional particles such as those employed in models of radiative neutrino mass generation. The scalar triplet realizations seem to be preferable with respect to the 2HDM benchmark and provide in the inert variant the dark matter candidates.

(The slides are now available)

Time and place: Jan. 27, 2016 1:05 PM, Ø467

Andrzej Hryczuk, FI

The thermal relic abundance of the dark matter is now determined observationally to a per cent level accuracy. It is also an increasingly useful tool to exclude, constrain or motivate models beyond the Standard Model of particle physics. It comes then with no surprise that in the recent years a considerable effort has been made to revise and improve some of the aspects of thermal relic density calculations. In this talk I will concentrate on the important physics concepts used in such calculations, highlighting some less commonly discussed details. Towards the end I will show some recent results, serving as examples of the relevance of the effects studied.

(The slides are now available)

Time and place: Jan. 22, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Viktoriya Yarushina (IFE) will give a talk on "Fluid flow in shales from experimental and theoretical perspective"

Time and place: Jan. 20, 2016 1:05 PM, Ø467

Chad Finley, Oskar Klein Centre (Stockholm)

The IceCube Neutrino Observatory lies two kilometers deep within the ice at the South Pole, Antarctica.  With one cubic kilometer of instrumented volume, IceCube enables the study of a wide range of phenomena: neutrino astronomy, dark matter searches, neutrino oscillations, and cosmic ray physics.  Recently IceCube has announced the long-awaited discovery of high energy neutrinos from deep space.  These neutrino energies are approximately 100 million times greater than the energies of neutrinos previously observed from the sun and supernovae. I will review IceCube's latest results with particular attention to this new flux. I will also discuss what we hope to measure in the near future with IceCube and the next generation of neutrino telescopes.

(The Slides are now available)

Time and place: Jan. 8, 2016 3:15 PM4:00 PM, Seminar room (FV414)

Yuri Galperin (Professor emeritus, Condensed matter physics, AMKS, UiO) will give a seminar in order to help us on (tentative plan) 1. How to write a referee report on a submission? 2. How to respond to referee's remarks (sometimes stupid)? 3. How to evaluate a grant application?

Time and place: Dec. 11, 2015 2:15 PM3:00 PM, FV414

Thi Thuy Luu (UiO, PGP) will talk about HBV (Buskerud and Vestfold University CollegeTønsberg, Norway) lab facilities. She will also talk about her PhD work that she did there about "Solid liquid interdiffusion (SLID) wafer-level bonding for MEMS packaging".

 

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Time and place: Dec. 4, 2015 4:15 PM5:00 PM, Seminar room (FV414)

This wine seminar reports on a field expedition/worskhop in the northern Patagonian Andes that involved 8 PGP people. The menu of the presentation is: volcanoes, amazing geology, stunning landscape, condors, gauchos and… Asado!!!   The presenters are, so far and not in order: - Olivier - Maya (to confirm) - Alban - Frank - Håvard.