Seminar on "Viable Bounce from Inflation" by Dr. Debottam Nandi
The Department of Physics, School of Natural Sciences, is pleased to invite students, faculty, and enthusiasts to an engaging seminar on "Viable Bounce from Inflation" by Dr. Debottam Nandi, DST-INSPIRE faculty at the University of Delhi. The seminar is scheduled for 18th September 2024 (Wednesday), from 2 PM to 3 PM (IST) at Room B-309.
Dr. Nandi, a distinguished researcher in the field of cosmology and theoretical physics, will delve into the intricate and fascinating concepts surrounding the early universe's inflationary period. His talk will explore the idea of a "bounce" – a theoretical model that proposes a universe rebounding from a prior contraction, instead of emerging from a singularity as suggested by the Big Bang model. Through this perspective, Dr. Nandi will discuss how inflationary theories can be extended to provide a more comprehensive understanding of the universe's origins and dynamics, as well as their implications for modern physics.
This seminar presents a unique opportunity to gain insights into cutting-edge research at the intersection of cosmology and quantum theory. Participants will have the chance to engage in discussions with Dr. Nandi and deepen their understanding of this evolving area of study.
The inflationary paradigm, a rapid acceleration of expansion, has been incredibly successful in explaining the dynamics of the early universe. However, it also faces several challenges, like the trans-Planckian/initial singularity problems and the abundance of models that are difficult to rule out. An alternative approach is the bouncing paradigm, where the universe contracts initially before expanding. Yet, constructing a viable bouncing model remains a significant challenge due to various instabilities, such as ghost and gradient issues. Moreover, these models often lack attractor properties, making them heavily dependent on initial conditions and prone to anisotropic instabilities.
In this talk, I'll delve into the construction of a classical bouncing model using a slow-roll inflationary model and employing conformal transformations. Through this approach, we can address the aforementioned instabilities and achieve a smooth transition from bouncing to the traditional reheating scenario. Additionally, I'll discuss the dynamical analysis of the system in the presence of a barotropic fluid, demonstrating that a wide range of model parameters can help avoid anisotropic instability, thus making this bouncing model a viable alternative to inflationary dynamics.
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