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- 25.10., Jonas Tjemsland (NTNU): The Almighty Axion
The Standard Model of particle physics has had immense success over the years. Yet, it has several shortcomings that illustrate its incompleteness, including for example the strong CP problem. However, already back in 1977 Peccei and Quinn postulated the existence of the so-called axion—a hypothetical, light pseudo-scalar boson—as a solution to the strong CP problem. Not only that, the axion and axion-like particles turn out to be potential miracle cures for many of the biggest problems humanity has ever faced: identifying dark matter, explaining dark energy, explaining inflation and ending world hunger. First, though, one must address the elephant in the room: the axion has not yet been detected. In this talk, I will give a theoretical introduction to the axion and its potential importance to modern physics, and I will discuss how the characteristic two-photon coupling enables the detection of axion-like particles. In particular, I will explain how axion-like particles can be detected by measuring photons from distant gamma-ray sources by exploiting a phenomenon known as ``photon-axion oscillation'' that occurs as photons propagate through astrophysical environments. - 28.10., Alexander Rothkopf (UiS): Open Quantum Systems: Thermometry at the Extremes
The study of quantum systems coupled to an environment plays a vital role in how we measure temperatures of the coldest and hottest matter in the universe. The strategy relies on introducing impurities into the system of interest and on observing how these probe particles evolve towards or in equilibrium with their surroundings, from which we may in turn deduce the thermal properties of that environment. Originally studied in the context of condensed matter physics, open quantum systems nowadays provide a common language to research spanning multiple orders of magnitude in temperature, ranging from Bose Einstein condensates made of ultracold atoms to the Quark-Gluon plasma created in ultra-relativistic collisions of heavy ions. This talk builds a bridge from polaron impurities in the former to quarkonium particles in the latter as two manifestations of quantum Brownian motion, a phenomenon ideally described by open quantum systems.
slides
- 15.11., David Garofalo (Kennesaw State University):
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