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. 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 model, 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, dilaton and tachyon. 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 k-essence using Markov Chain Monte Carlo method. Data used include Planck 2018 data and Pantheon+SH0ES from SH0ES collaboration. We find $H_0\,=\, 68.48\,\pm\,0.72\, \text{km/s/Mpc}$ in dilaton model and $70.00\,\pm\,0.63\text{km/s/Mpc}$ in tachyon model using Planck data alone, showing a mild $3.60\sigma$ and $2.50\sigma$ tensions, respectively, with SH0ES measurement. Using Pantheon+SH0ES dataset, the tension with Planck data reduces from $8.80\sigma$ using $\Lambda$CDM model to $5.41\sigma$ and $3.85\sigma$ using dilaton and tachyon models, respectively. Although the tension still exists between CMB and the local measurement datasets, k-essence dark energy promises better results than $\Lambda$CDM in the context of Hubble tension.
| Stream | Science or Engineering |
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