Swampland criteria for a dark-energy dominated universe, ensuing from Gaussian process and H(z) data analysis (1811.03861v2)

Abstract: Implications of the string Swampland criteria for a dark energy dominated universe, obtained by using Gaussian processes and $H(z)$ data analysis, are discussed. In particular, the Swampland criteria for a scalar-field dark energy, without assuming any specific form for the potential. By allowing the Gaussian process to reconstruct the form of the potential from $H(z)$ data, upper bounds on the second Swampland criterion (involving $|V^{\prime}|/V$) for two different kernel functions (the squared exponential and Matern~($\nu = 9/2$) kernels) are estimated . The approach here differs from previous studies, since the upper bound of the second Swampland criterion is derived in a thoroughly model-independent way, without resorting to a model-to-model comparison strategy. The analysis is performed using the latest values of $H_{0}$ reported by the Planck and Hubble missions. Results for the estimation of the constant of $SC2$ hint towards the possibility of getting upper bounds well behind the estimations for the dark energy dominated universe as reported in previous studies, which involved model-to-model comparison. Estimations from this new approach turn to be quite sensitive and just depend on the quality of the data and on the kernel employed. This study is a first attempt towards the exploitation of the Swampland criteria in a model-independent way and may be extended to involve other datasets and, also, in trying to understand what is the impact of higher-redshift data on the upper bounds. In the analysis, $40$-point $H(z)$ data have been used, consisting of a $30$-point sample deduced from a differential age method and an additional $10$-point sample obtained from the radial BAO method. Hints towards the possibility of eventually disproving the Swampland conjecture are noted.