NEC violation in $f(\bar{R},\bar{T})$ gravity in the context of a non-canonical theory via modified Raychaudhuri equation

Abstract

In this work, we develop the Raychaudhuri equation in $f(\bar{R},\bar{T})$ gravity in the setting of a non-canonical theory, namely K-essence theory. We solve the modified Raychaudhuri equation for the additive form of $f(\bar{R},\bar{T})$, which is $f_1(\bar{R})+f_2(\bar{T})$. For this solution, we employ two different scale factors to give two types of $f(\bar{R},\bar{T})$ solutions. The ongoing debate between Fisher et. al. and Harko et. al. in 2020 regarding the additive form of $f(\bar{R},\bar{T})$ may provide a resolution within the modified $f(\bar{R},\bar{T})$ gravity theory. By conducting a viability test and analyzing energy conditions, we have determined that in the first scenario, the null energy condition (NEC) is violated between two regions where the NEC is satisfied. Additionally, we have observed that this violation of the NEC exhibits a symmetric property during the phase transition. These observations indicate that bouncing events may occur as a result of the symmetrical violation of the NEC during the expansion of the universe. Moreover, this model indicates that resonant-type quantum tunneling may take place during the period when the NEC is violated. The findings of NEC violation through the power law of scale factor may have empirical relevance in contemporary observations. In the second scenario, our model indicates that the strong energy condition is violated, but the NEC and weak energy conditions are satisfied. The effective energy density decreases and is positive, while the effective pressure and equation of state parameters are negative. This suggests that the universe is expanding with acceleration and is dominated by dark energy.

29 pages, 37 figures, 4 tables, Comments invited

References in corpus (32)

• f(R,T) gravity
• Exploring gravitational theories beyond Horndeski
• Aspects of the cosmological "coincidence problem"
• The 1965 Penrose singularity theorem
• Stability of Cosmological Solution in f(R) Models of Gravity
• Theoretical Models of Dark Energy
• The Raychaudhuri equations: a brief review
• Stellar equilibrium configurations of white dwarfs in the $f(R,T)$ gravity
• Anomalies in Physical Cosmology
• The dark energy equation of state
• Hidden Negative Energies in Strongly Accelerated Universes
• Limits on $f(R,T)$ Gravity from Earth's Atmosphere
• On the Null Energy Condition and Cosmology
• Power-law cosmology, SN Ia, and BAO
• Energy conditions bounds and their confrontation with supernovae data
• Evaluation of cosmological models in $f(R,T)$ gravity in different dark energy scenario
• Null Energy Condition Violation and Classical Stability in the Bianchi I Metric
• Reconstruction of $f(R)$ gravity models for an accelerated universe using Raychaudhuri equation
• Null energy condition violation during inflation and pulsar timing array observations
• Holographic kinetic k-essence model
• Reconstruction of $f(R,T)$ gravity model via the Raychaudhuri equation
• Transit cosmological models in Myrzakulov F(R,T) gravity theory
• Raychaudhuri equation in $k$-essence geometry: conditional singular and non-singular cosmological models
• Perturbative unitarity and NEC violation in genesis cosmology
• The Hawking temperature in the context of dark energy for Kerr-Newman and Kerr-Newman-AdS backgrounds
• Energy conditions bounds and supernovae data
• Raychaudhuri equations and gravitational collapse in Einstein-Cartan theory
• Thermodynamics for the k-essence Emergent Reissner-Nordstrom-de Sitter Spacetime
• Response to Comment on "Reexamining $f(R,T)$ Gravity''
• Geodesic structure of generalized Vaidya spacetime through the K-essence
• Self Similar Collapse and the Raychaudhuri equation
• An accelerated universe with negative equation of state parameter in Inhomogeneous Cosmology with $k$-essence scalar field

Cited by in corpus (5)

• Modified $f(R,T)$ theory in light of gravitational wave standard sirens
• Non-Affine Extensions of the Raychaudhuri Equation in the K-essence Framework
• On the Field Theoretical Description of an Alternative Model to Generalized Chaplygin Gas and its Thermodynamic Behaviour
• Exploring Cosmological Implications of the Modified Raychaudhuri Equation in Non-Gravitating Vacuum Energy Theory
• From Geometry to Observation: Gravitational Waves and the Raychaudhuri Equation