Kinetically Coupled Scalar Fields Model and Cosmological Tensions
In this paper, we investigate the kinetically coupled early dark energy (EDE) and scalar field dark matter to address cosmological tensions. The EDE model presents an intriguing theoretical approach to resolving the Hubble tension, but it introduces challenges such as the "why then" problem of why EDE was injected during the epoch of matter-radiation equality, and exacerbates existing large-scale structure tension. Therefore, we consider the interaction between dark matter and EDE, such that the dynamics of EDE are triggered by the dark matter, and the drag effect of dark energy on dark matter suppresses structure growth, which can alleviate large-scale structure tension. We replace cold dark matter with scalar field dark matter, which has the property of suppressing structure growth on small scales. We employed the Markov Chain Monte Carlo method to constrain the model parameters by utilising a variety of cosmological data, our new model reveals a non-zero coupling constant of $0.030 \pm 0.026$ at a 68\% confidence level. The coupled model yields a Hubble constant value of $72.38^{+0.71}_{-0.82}$ \,km\,/\,s\,/\,Mpc, which resolves the Hubble tension. However, similar to the EDE model, it also obtains a larger $S_8$ value compared to the $\Lambda$CDM model, further exacerbating the large-scale structure tension. The best-fit $S_8$ value for the EDE model is $0.8316$, whereas our new model yields a smaller value of $0.8134$. Additionally, the coupled model exhibits a smaller $\chi^2_\mathrm{tot}$ value compared to the EDE model and the $\Lambda$CDM model, indicating a better fit to the data.