Events at Physics
Events on Tuesday, November 9th, 2021
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- Quarkyonic model for neutron stars
- Time: 2:00 pm - 3:00 pm
- Speaker: Srimoyee Sen , Iowa State University
- Abstract: The observed mass and radius relations of neutron stars can be explained remarkably well using a model of dense matter known as quarkyonic matter. I describe how the quarkyonic matter can arise dynamically from an excluded volume model for nuclear interactions and how thermal effects can be incorporated in such a model. I also discuss how one can improve the excluded volume model to correctly reproduce low energy nuclear interactions and recover mass radius relations of neutron stars.
- Host: Baha Balantekin
- Theory Seminar (High Energy/Cosmology)
- Precision Calculation of Inflation Correlators at One Loop
- Time: 4:00 pm - 5:00 pm
- Place: Chamberlin 5280
- Speaker: Yiming Zhong, KICP
- Abstract: We initiate a systematic study of precision calculation of the inflation correlators at the 1-loop level, starting in this paper with bosonic 1-loop bispectrum with chemical-potential enhancement. Such 1-loop processes could lead to important cosmological collider observables but are notoriously difficult to compute due to the lack of symmetries. We attack the problem from a direct numerical approach based on the real-time Schwinger-Keldysh formalism and show full numerical results for arbitrary kinematics containing both the oscillatory "signals" and the "backgrounds". Our results show that, while the non-oscillatory part can be one to two orders of magnitude larger, the oscillatory signal can be separated out by applying appropriate high-pass filters. We have also compared the result with analytic estimates typically adopted in the literature. While the amplitude is comparable, there is a non-negligible deviation in the frequency of the oscillatory part away from the extreme squeezed limit. See arXiv:2109.14635 for more details.
- Host: Lars Aalsma