Banca de DEFESA: FRANCISCO THIARLY ALVES DE SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FRANCISCO THIARLY ALVES DE SOUZA
DATE: 29/04/2026
TIME: 09:30
LOCAL: Google Meet
TITLE:

Effects of a Viscous Dark Energy Model on the Cosmological Background

KEY WORDS:

Standard model; Tension; Viscous dark energy; Background

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

In the context of modern cosmology, the simplest mathematically consistent model in agreement with observational data, and therefore regarded as the standard model, is the ΛCDM framework. Nevertheless, persistent tensions and conceptual challenges have motivated ongoing efforts to explore extensions capable of preserving its robustness while addressing such issues. A viable modification consists in relaxing the perfect-fluid assumption for dark energy and allowing for dissipative processes, thereby promoting a more generalized cosmological scenario. In this work, the fundamental equations were modified to investigate the effects of introducing bulk viscosity into the dark energy sector, analyzing its impact on both the cosmological background dynamics and observational viability. To this end, a more general entropic formulation was considered, encompassing non-extensive regimes, together with a specific model describing the evolution of viscosity. This approach introduced two additional parameters into the analysis, providing controlled flexibility to adjust the model to observational data. The resulting equations were solved numerically using the CLASS code, and the outcomes were systematically compared with the standard ΛCDM model. Overall, the viscous model proved to be dynamically stable and consistent with well-established cosmological physics, remaining in agreement with current observational constraints. These results support its viability as a plausible extension of the standard cosmological scenario.

COMMITTEE MEMBERS:
Interno - 1043096 - FARINALDO DA SILVA QUEIROZ
Externo à Instituição - JOSE FERNANDES DE JESUS
Presidente - 1390849 - RODRIGO FERNANDES LIRA DE HOLANDA