HELSINKI INSTITUTE OF PHYSICS SEMINARS
HIP seminar room A315
- Friday 24 May 2019 at 13.15 in D101: Frank Wilczek (MIT and Stockholm)
Axion plasmon converter
Abstract: Axions are hypothetical particles whose existence would solve an important problem in fundamental physics and supply the dark matter of the universe. I will briefly review the motivations for axions and the status of experimental searches, and then describe a new approach which appears quite promising.
Frank Wilczek will in Helsinki also attend this event on Saturday.
- Thursday 13 June 2019 at 10.15 in A315: Sebastian Schuster (Wellington Univ)
Sparsity – Quantifying the Difference Between Hawking Radiation and Black Body Radiation
Abstract: In the mid-1970s, Stephen Hawking discovered the evaporation of black holes. Since then it has not just become a hallmark of quantum field theory in curved space-time, but also one of the most important clues towards a quantum theory of gravity. The subsequent decades have seen advances of formal, numerical, and pedagogical nature; yet just as much formation of folklore. Core and center to both folklore and advances is the comparison of black hole radiation to black body radiation. In this talk we shall present a heuristic quantity, “sparsity”, for quickly performing this comparison. This quantity is simple to explain, easy to calculate, and helps illustrate the differences and commonalities of the two types of radiation. Beyond this, it is also possible to extend results from the original, 3+1-dimensional contexts to higher dimensions. We can reproduce some results regarding the different emission characteristics of different particle species in higher dimension known from previous numerical studies in the literature.
- Thursday 27 June 2019 at 10.15 in A315: Suvankar Dutta (IISER Bhopal India)
- Tuesday 27 August 2019 at 10.15 in A315: Tommi Tenkanen (Johns Hopkins University)
Spectator Dark Matter
Abstract: The observed dark matter abundance in the Universe can be fully accounted for by a minimally coupled spectator scalar field that was light during inflation and has sufficiently strong self-coupling. In this scenario, dark matter was produced during inflation by amplification of quantum fluctuations of the spectator field. The self-interaction of the field suppresses its fluctuations on large scales, and therefore avoids isocurvature constraints. The scenario does not require any fine-tuning of parameters. I will also discuss ways to test the scenario.
- Tuesday 27 August 2019 at 14.15 in A315: Tiina Naaranoja (University of Helsinki)
Diamond Time-of-Flight Detectors and their Radiation Tolerance
Hopefully the up to 50 min + 10 min discussion long seminar/colloquium will be understandable to a wide audience.
Contacts: Keijo Kajantie (keijo kajantie at helsinki fi) [ HIP seminar],
Sofie Koksbang (sofie koksbang at helsinki fi) [cosmo seminar]
For older seminars, click Seminar Archive on top of page
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