Study of the Models of Viscous Modified Gravity and Validation Through Probabilistic Information Theory

---

Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: AMITY UNIVERSITY KOLKATA , AMITY INSTITUTE OF APPLIED SCIENCES, Mathematics, Hindistan

Tezin Onay Tarihi: 2024

Tezin Dili: İngilizce

Öğrenci: SANGHATI SAHA

Asıl Danışman (Eş Danışmanlı Tezler İçin): Surajıt Chattopadhyay

Eş Danışman: Ertan Güdekli

Özet:

Cosmology, the study of the universe, has advanced significantly in the previous several decades. At this time, cosmology, like other branches of physics, is dependent on observations. In recent years, high-precision observation technologies have emerged. Contrary to all expectations, the high-precision data leads to the unexpected conclusion that the universe is expanding with acceleration. In accordance with the PhD thesis objectives, the work began with modified gravity models in which the bulk viscosity was integrated via bulk viscous pressure in addition to the thermodynamic pressure of the modified Friedmann’s equations. Taking the background fluid in the form of GCG and MGCG into account, we conducted a thorough analysis of the cosmological repercussions and investigated the behaviour of the EoS parameter. Notably, certain situations show avoidance of future singularities. Because our research focused on the cosmological implications of probabilistic information theory, we performed an information-theoretic examination of the models built using SDSS DR7 observations. Entropy optimization is a critical method to probabilistic information theory, and we accomplished the same by tracking the evolution of Shannon entropy with the evolution of the universe. Keeping in mind recent cosmological efforts to reconcile the early scenarios of the universe with late-time acceleration, we expanded our research in that direction, and bulk viscosity was primarily considered for the unification models. The associated cosmology with redshift was investigated using probabilistic information theory. In this context, we also considered modified gravity, and we investigated various elements of bounce realisation using different scale factors. In the final phase of the study, we investigated sign-changeable interactions in a two-fluid situation within a bulk viscous framework. The PhD research was primarily focused on viscous-modified gravity models, and it carefully studied the cosmological ramifications of such considerations using probabilistic information theory. This study experimented with bulk viscosity in various forms and investigated unification scenarios while taking bulk viscosity into account. Finally, the researchers studied the GSL of thermodynamics and interpreted it in light of the universe’s accelerating expansion