Friday Seminar
The Cosmology Lunch Seminar are scheduled on Fridays from 12 p.m.-1 p.m.
All Seminars will be hosted In-Person | Goldwater Building 5th floor | Conference room 505
Spring 2024 Speakers
Albin Joseph - January 19, 2024
Date: 1/19/2024
Speaker: Albin Joseph
Institution: ASU
Faculty Host: Simon Foreman
Title: Dynamics of Dark Energy: Cosmological Trackers
Abstract: Two decades have passed since the groundbreaking discovery of cosmic acceleration, yet the mysteries surrounding the laws of physics on the largest scales persist. This remarkable phenomenon, initially revealed through the observation of type 1a supernovae, has revolutionized our comprehension of cosmology and serves as a paradigm shift in our understanding of the Universe. In this talk, I will discuss the cosmological models exhibiting tracker properties that have great significance in the context of dark energy as they can reach the present value of dark energy density from a wide range of initial conditions, thereby alleviating both the fine-tuning and the cosmic coincidence problem. In particular, I will discuss the Oscillatory Tracker Model, which belongs to the family of tracker dark energy models and their effect on various observational probes.
Tarun Souradeep - March 22, 2024
Date: 3/22/24
Speaker: Tarun Souradeep
Institution: Raman Research Institute
Faculty Host: Tanmay
Title: Validating the Cosmological principle
Abstract: The Cosmological Principle, a fundamental tenet of the 'standard model of cosmology', predicates a statistically isotropic distribution of fluctuations in the measured Cosmic Microwave Background (CMB) temperature and polarisation sky maps. Enigmatic anomalies claimed in the WMAP and Planck CMB sky maps, and some other recent observations could challenge the standard model. However, these claims need to be cast in an objective mathematical framework and established with statistical rigour. Bayesian inference of the underlying covariance structure of random fields on the sphere in the Bipolar Spherical Harmonic (BipoSH) representation developed in our research program provides such a framework. We review the recent inferences drawn from Planck data and dwell on the future prospects with proposed CMB observations.
Damien Easson - March 29, 2024
Date: 3/29/24
Speaker: Damien Easson
Institution: ASU
Faculty Host: Matt
Title: Solving the initial singularity problem: eternal inflation and a world without end
Abstract:
We discuss the possibility an eternal universe, a universe with no first moment and no end.
The talk will focus on eternal inflation and the key role that inflation plays in resolving the initial big-bang singularity.
Along the way we, will describe how proposed no-go theorems, such as the famous theorem of Borde, Guth and Vilenkin (BGV)
are circumvented or obviated. Our exploration encompasses eternal inflating, loitering, and bouncing models, shedding light on
the critical aspects that underpin geodesic completeness. This will include a detailed analysis of the classical energy conditions in General Relativity.
Ignoring the intractable subtleties introduced by quantum considerations, such as rare tunneling events and
Boltzmann brains, we will argue that the universe need not have a beginning or an end.
Yosef Verbin - April 12, 2024
Date: 4/12/24
Speaker: Yosef Verbin
Institution:
Faculty Host: Damien
Title: Palatini Nonlinear Electrodynamics
Abstract: The general subject of this talk is the formulation of electrodynamics and its non-linear generalizations, in an analogy with the Palatini formalism of General Relativity and its extensions and modifications. As in GR, the first order formulation of Maxwell theory is equivalent to the second order standard formulation since the field equations are identical. Moreover, for theories of nonlinear electrodynamics, the situation is similar to that of gravity and in certain cases, the first and second order formulations yield different field equations. Some of the initial results of the most basic implications of these Palatini non-linear electrodynamics (PNLED for short) will be presented – mainly as compact objects like solitons and black holes. If time permits, cosmological implications will be mentioned briefly.
Francesc Ferrer - April 19, 2024
Date: 4/19/24
Speaker: Francesc Ferrer
Institution:
Faculty Host: Tanmay
Title:
Abstract: