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Department of Physics and Astronomy

Nuclear, Astro and Particle Physics Seminars

These lectures feature speakers from around the country and globe. Each seminar lasts about an hour and takes a closer look at more specialized fields in various realms of physics and astronomy.

Many seminars will be held in a hybrid format and a recurring Zoom link is provided to access the virtual format.

The talks will be on Wednesdays at 4PM in the Rogers Room (Jones PSC 409).

Upcoming Seminar (Fall 2024):

Waiting for Inflation: A New Initial State for the Universe

Speaker: Arnab Pradhan
Affiliation: 
Date: October 30th

Abstract: We propose a cosmological lingering phase for the initial state prior to inflation which would help address the singularity problem of inflation. The universe begins with a constant (Hagedorn) temperature and then transitions into an inflationary universe while preserving the Null Energy Condition (NEC). In such a universe time is presumably emergent, calling the age of the universe into question. We first consider the phase space of positive spatial curvature models within General Relativity and with matter sources that respect the NEC. Depending on the duration of the post-lingering inflation these models can produce a small amount of observable spatial curvature in the Cosmic Microwave Background. We also discuss how lingering can arise with or without spatial curvature in theories of quantum gravity when considering the thermodynamic scaling of particles and its impact on the early universe. The string theory dilaton is essential to the dynamics. There are many open questions that remain.

Fall 2024 Calendar:

Date Speaker Title of Seminar
9/4/24 Itay Bloch Snipe Hunt: using the largest cavities on earth to search for DM
9/18/24 Steven Elliott Isomers and Dark Matter: 180mTa and 178mHf
9/24/24 Frank Avignone The Quest Discover Dark Matter and A New Search at USC
10/2/24 Maura McLaughlin The discovery and promise of Fast Radio Bursts
10/30/24 Arnab Pradhan Waiting for Inflation: A New Initial State for the Universe
11/06/24 Scott Watson TBA
11/13/24 Xincheng Lin TBA
11/20/24 Rodolfo Capdevilla TBA
01/22/25 Garrett King TBA

Challenge the conventional. Create the exceptional. No Limits.

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