Tsallis Holographic Dark Energy Reconsidered

Abstract

We consider the Interacting Tsallis Holographic Dark Energy (THDE) as dynamical vacuum, with the Granda-Oliveros (GO) scale as the infrared (IR) cutoff. To probe the evolution of the spatially flat Friedmann Lemaître Robertson Walker (FLRW) universe with dark energy and matter components, we analytically solved for the Hubble parameter, and the solution traces the evolutionary path from the prior decelerated to the late accelerated epoch. We used Pantheon Supernovae type Ia and Observational Hubble Data to constrain the free parameters of the model. The estimated values of the cosmological parameters were consistent with observational results. We analysed the behaviour of the model using the statefinder and ω e − ω e plane, and the model shows a quintessence behaviour in general and approach ΛCDM in the future. We performed a dynamical analysis of the model, concluding that the prior decelerated and late accelerated phases are unstable and stable equilibria, respectively. We also investigated the thermodynamical nature of the model and found that the horizon entropy is always an increasing function of time; the generalised second law remains valid in the dynamical vacuum treatment of the model.