Speaker
Description
Hubble tension remains a major problem in modern cosmology due to the fact that it challenges $\Lambda$CDM model. The solution to this puzzle has been found to revolve around dynamical dark energy and interacting dark sector. K-essence is one of the numerous dark energy models first developed to explain inflation, then the accelerated expansion of the Universe. Unlike $\Lambda$CDM, k-essence is an effective scalar field theory described by a pressure Lagrangian with a non-canonical kinetic term, and a freely evolving equation-of-state parameter. We examine two k-essence models with and without interactions between k-essence dark energy and cold dark matter. We constrain the parameters: $\{H_0,\, \Omega_{b}h^2,\, \Omega_ch^2\}$ with $\lambda$ and $A_0$ for dilaton model; and $\alpha$ and $A_0$ for tachyon field model without interactions using MCMC method. With interaction, additional parameter, $\xi$ represents interaction strength, where we consider energy transfer from cold dark matter to k-essence dark energy, when $\xi\,>\,0$. Data used include Planck 2018 data; the Hubble parameter data from cosmic chronometer method, BAO signal in galaxy distribution, and BAO signal in Ly$\alpha$ forest distribution alone; the value of Hubble parameter from SH0ES; the three-year data (DR2) release from the DESI collaboration; and Supernovae Type Ia data, i.e. Union3, DESY5, and Pantheon+SHOES. We find $H_0\,=\,70.50\,\pm\,0.65\,\text{km/s/Mpc}$ in dilaton and $70.00\,^{+0.97}_{-0.72}\,\text{km/s/Mpc}$ in tachyon using Planck data alone, showing a mild $2.07\sigma$ and $2.27\sigma$ tensions, respectively, with SH0ES measurement. Using Pantheon+SH0ES dataset, the tension with Planck data reduces from $8.62\sigma$ using $\Lambda$CDM to $4.07\sigma$ and $3.27\sigma$ without interaction; and $2.51\sigma$ and $3.40\sigma$ with interaction using dilaton and tachyon field k-essence models, respectively. Local measurement data combinations show great reduction in the tension with CMB (Planck) and SH0ES measurements. Although the tension still exists between CMB and local measurement datasets, k-essence dark energy promises better results than $\Lambda$CDM in the context of Hubble tension.
| Stream | Science or Engineering |
|---|