Reconstruction of the swampland conjectures with DESI DR1 BAO data

Abstract

The swampland conjectures (SCs) propose constraints on effective field theories that can arise from a consistent theory of quantum gravity. Two prominent SCs suggest that the scalar field excursion and the gradient of the potential should be at most $\mathcal{O}(1)$ in Planck units. Using the first data release from the Dark Energy Spectroscopic Instrument (DESI) survey and model-independent reconstructions of the SC-related quantities at late times, via a machine learning approach known as genetic algorithms, we evaluate the consistency of these reconstructions with the SC expectations. Our results indicate that the reconstructed second SC is several sigmas away from zero, suggesting a steep potential, in contrast to recent model-specific analyses assuming exponential potentials. The novelty of our approach lies in using solely model-independent reconstructions of cosmological observables from DESI, such as the angular diameter distance and the Hubble expansion history. This makes our method readily applicable to forthcoming data from stage IV surveys, providing a framework for further assessing consistency with SCs.

Figures (3)

• Figure 1: The GA reconstruction of the first and second swampland conjectures on the left and center panels respectively, along with the $\Gamma$ parameter (right panel), which is related to the second derivative of the potential, see Eq. \ref{['eq:gamma']}.
• Figure 2: Left panel: Shape of the dimensionless potential (see Eq. \ref{['eq:Vx']}) as a function of $\tilde{\phi}$ from our GA reconstruction with different values of the matter density $\Omega_\mathrm{m,0}$. In all cases one can see that the potential is steep. Middle panel: The GA reconstruction of the second swampland conjecture defined as $\lambda$ with different values of the matter density $\Omega_\mathrm{m,0}$ which serves to highlight that despite the reasonable value of $\Omega_\mathrm{m,0}$ one uses, the shape maintains a similar form. Right panel: Plot of $\Gamma$ as defined in Eq. \ref{['eq:gamma']} for different values of the matter density $\Omega_\mathrm{m,0}$.
• Figure 3: Reconstructions of a scalar-field potential $V$ (left) and the parameters $\lambda$ (middle) and $\Gamma$ (right), based on the DESI $w_0-w_a$ best-fit. As at some point the scalar field kinetic term becomes negative, the reconstruction fails. Still, the general properties of the reconstructed parameters of the scalar field, are consistent with our GA fits.