Bulk Viscous Flat FLRW Model with Observational Constraints in <i>f</i>(<i>T</i>, <i>B</i>) Gravity

Abstract

This paper investigates the impact of bulk viscosity within the framework of f(T,B) gravity. We consider a time-dependent viscosity model with a particular Hubble parameter expression. Here, we looked into the viability of well-motivated f(T,B) gravity model, which takes the form f=αlog(B)+βT, and has free parameters α and β. The 46 observational Hubble data (OHD) in the range 0≤z≤2.36 were used to constrain the model parameters to achieve the solution. We have used the Markov Chain Monte Carlo (MCMC) method to estimate model parameters and observe that the model appears to be in good agreement with the observations. In addition, we evaluate the effective viscous equation of state parameter for the f(T,B) model. We have examined the characteristics of different energy conditions for the stability analysis. The model is valid based on the positive behavior of null energy conditions (NEC), weak energy conditions (WEC), and dominant energy conditions (DEC); however, strong energy conditions (SEC) are in violation, suggesting that the universe is expanding faster. Our model was found in the quintom region. We also discussed how the tachyon scalar field corresponds to f(T,B) gravity.

Keywords

• modified gravity
• cosmology
• <i>f</i>(<i>T</i>, <i>B</i>) gravity
• viscosity