Cosmological dynamics of FRW universe in presence of tachyonic field

Abstract In this work, we investigate the cosmological dynamics of the Universe in scenarios where the tachyonic field dominates, exhibiting both its normal characteristics and phantom behavior, over the energy density of matter and radiation. When the time derivative of the tachyon field, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>ϕ</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>̇</mml:mo> </mml:mrow> </mml:mover> </mml:math> , is very small, we observe that the nature of the scalar field and the potential play pivotal roles in the evolution of the Universe. We further analyze the dynamic features using various parameters, including the deceleration parameter q , the equation of state (EoS) parameter, the squared sound speed, and the Om diagnostic. Additionally, we discuss the Universe’s evolution in the parametric planes of { r , s } and ω - <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>ω</mml:mi> <mml:mo accent="false">′</mml:mo> </mml:math> .