Abstract
In this Letter, we consider the model-independent reconstruction of the expansion and growth functions from the Pantheon supernova data. The method relies on developing the expansion function in terms of shifted Chebyshev polynomials and determining the coefficients of the polynomials by a maximum-likelihood fit to the data. Having obtained the expansion function in a model-independent way, we can then also determine the growth function without assuming a particular model. We then compare the results with the predictions of two classes of Dark Energy models, firstly a class of quintessence scalar field models consistent with the trans-Planckian censorship and swampland conjectures, and secondly a class of generalized Proca vector field models. We determine constraints on the parameters which appear in these models.
Highlights
The origin of Dark Energy is one of the outstanding mysteries of contemporary physics. Could it be that the nature of Dark Energy could teach us something about quantum gravity? Quantum gravity is a theory still in its infant form and under continuous development with the aim to unite quantum physics and general relativity
We will study the implications of the swampland conjectures for Dark Energy. Both the de Sitter conjecture and the transPlanckian censorship” conjecture (TCC) imply that pure de Sitter space is incompatible with string theory, and lead to stringent constraints on early universe cosmology
We find that given the current accuracy of the observations, there is already a difference between the predictions of the vanilla ΛCDM model and quintessence models which are preferred by the swampland arguments
Summary
The origin of Dark Energy is one of the outstanding mysteries of contemporary physics. It is believed that general relativity could be the low energy limit of the more fundamental superstring theory The latter represents a possible UV completion of gravity based on the idea that the fundamental building blocks of nature are strings with one-dimensional spatial extent instead of point-like elementary particles which underlie the usual quantum field theories. Since the 1980s, string theory is considered as the most promising candidate for a theory unifying all forces of nature at the quantum level, combining the standard model of elementary particle physics and gravitation. We will study the implications of the swampland conjectures for Dark Energy Both the de Sitter conjecture and the TCC imply that pure de Sitter space is incompatible with string theory, and lead to stringent constraints on early universe cosmology. We find that the deviations in the expansion and growth functions in the Proca model (compared to those of the ΛCDM) have the opposite sign compared to those in quintessence models
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