• Shashi Narayan Shukla
• Dr. R.K. Dubey

This paper explores the recent advancements in understanding the accelerated expansion of the universe, emphasizing the role of dark energy (DE) and alternative gravitational theories. Observations, such as those from the Supernova Cosmology Project, the Wilkinson Microwave Anisotropy Probe (WMAP), and the Sloan Digital Sky Survey (SDSS), have consistently indicated an ongoing accelerated expansion. The universe is currently composed of approximately 68.3% dark energy, 26.8% dark matter, and 4.9% baryonic matter, with DE being a primary driver of cosmic acceleration. We discuss the role of the cosmological constant, quintessence, phantom, k-essence, tachyons, and Chaplygin gas as potential representations of DE. The paper further explores modified theories of gravity, including f(R), f(G), f(T), and f(R, T) gravity, as alternative explanations for cosmic acceleration. Specifically, we examine the f(R, T) gravity model, utilizing the field equations and a proposed variation in the Hubble parameter H as a function of cosmic time. The approach presented provides insights into the behavior of the universe's expansion based on empirical data and generalized gravitational actions. This study contributes to our understanding of cosmic acceleration, exploring both dark energy models and modifications to Einstein's general relativity. Future research directions involve refining these models to better align with observational data and improve the understanding of the fundamental nature of dark energy.

"Exploring Accelerated Cosmic Expansion: Dark Energy Models and Modified Gravity Theories in f(R, T) Cosmology", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.11, Issue 11, page no.d188-d195, November-2024, Available :http://www.jetir.org/papers/JETIR2411323.pdf

"Exploring Accelerated Cosmic Expansion: Dark Energy Models and Modified Gravity Theories in f(R, T) Cosmology", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.11, Issue 11, page no. ppd188-d195, November-2024, Available at : http://www.jetir.org/papers/JETIR2411323.pdf