Related papers: Dark Energy in the Swampland
We consider the implications of the swampland conjectures on scalar-tensor theories defined in the Einstein frame in which the scalar interaction is screened. We show that chameleon models are not in the swampland provided the coupling to…
String theory naturally leads to the expectation that dark energy is not stable, and may be evolving as captured by the Swampland de Sitter conjectures. Moreover, motivated by the distance conjecture, a unification of dark sector has been…
A six parameter cosmological model, involving a vacuum energy density that is extremely tiny compared to fundamental particle physics scales, describes a large body of increasingly accurate astronomical data. In a first part of this brief…
We consider quintessence models within 4D effective descriptions of gravity coupled to two scalar fields. These theories are known to give rise to viable models of late-time cosmic acceleration without any need for flat potentials, and so…
Motivated by principles from the Swampland program, which characterize requirements for a consistent UV completion of quantum gravity, combined with observational data, we are led to a unique corner of the quantum gravity landscape. In…
Recently a swampland criterion has been proposed that rules out de Sitter vacua in string theory. Such a criterion should hold at all points in the field space and especially at points where the system is on-shell. However there has not…
It was recently pointed out that the cosmological constant (even metastable one) belongs to the so-called "swampland" and hence cannot be obtained as the low-energy limit of string theory that requires $|\nabla V| > c V$. If true, the dark…
While $\Lambda$CDM provides a good fit to cosmological data, it fails to address many of the outstanding questions in contemporary cosmology. Chief among these are the Hubble tension and the apparent dynamical nature of dark energy as…
Recently, the observed equation of state for dark energy appears to favor values below $-1$. The tendency implies that the nature of dark energy may be quite different from that of the cosmological constant. In view of the adjustment on the…
The high-quality cosmological data, which became available in the last decade, have thrusted upon us a rather preposterous composition for the universe which poses one of the greatest challenges theoretical physics has ever faced: the…
Cosmic surveys provide crucial information about high energy physics including strong evidence for dark energy, dark matter, and inflation. Ongoing and upcoming surveys will start to identify the underlying physics of these new phenomena,…
We present a Dark Energy (DE) model with a sound derivation as a natural extension of the Standard Model of particle physics with no free parameters and an excellent fit with current cosmological data improving by 21% the $\Lambda$CDM fit…
We present a Bayesian comparative analysis of five cosmological models: $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, $\phi$CDM (with scalar-field dark energy), and an interacting dark energy scenario (the $\xi$-index model), to investigate dark…
We study a string-motivated theoretical prior on the quintessential dark energy model with exponential potential, \( V(\phi) = V_0 e^{-\lambda \phi} \), allowing for non-zero spatial curvature. First, we formulate the corresponding…
Major observational efforts in the coming decade are designed to probe the equation of state of dark energy. Measuring a deviation of the equation-of-state parameter w from -1 would indicate a dark energy that cannot be represented solely…
The ``Swampland Program'' aims to discriminate consistent-looking effective field theories that do not admit a UV completion in quantum gravity from those that do. While most often developed under the umbrella of string theory, several…
The recently proposed Swampland Criteria aim to evade any (meta-)stable de Sitter constructions within String landscapes, making it difficult to accommodate accelerating phases, like dark energy domination and inflationary epoch, in…
Motivated by the early discovery of the gigantic landscape of string theory vacua, in recent years people switched direction to try to find constraints on low energy effective field theories from UV-complete descriptions for example quantum…
Future cosmological surveys will probe the expansion history of the universe and constrain phenomenological models of dark energy. Such models do not address the fine-tuning problem of the vacuum energy, i.e. the cosmological constant…
We consider the interplay of the Early Dark Energy (EDE) model, the Swampland Distance Conjecture (SDC), and cosmological parameter tensions. EDE is a proposed resolution of the Hubble tension relying upon a near-Planckian scalar field…